diff --git a/flink-process-function-parent/flink-process-function-api/src/main/java/org/apache/flink/process/api/context/RuntimeContext.java b/flink-process-function-parent/flink-process-function-api/src/main/java/org/apache/flink/process/api/context/RuntimeContext.java
index dd9b2c8a3be0b..bdcd731ca1a37 100644
--- a/flink-process-function-parent/flink-process-function-api/src/main/java/org/apache/flink/process/api/context/RuntimeContext.java
+++ b/flink-process-function-parent/flink-process-function-api/src/main/java/org/apache/flink/process/api/context/RuntimeContext.java
@@ -37,4 +37,7 @@ public interface RuntimeContext {
 
     /** Get the {@link StateManager} of this process function. */
     StateManager getStateManager();
+
+    /** Get the {@link ProcessingTimeManager} of this process function. */
+    ProcessingTimeManager getProcessingTimeManager();
 }
diff --git a/flink-process-function-parent/flink-process-function-api/src/main/java/org/apache/flink/process/api/function/OneInputStreamProcessFunction.java b/flink-process-function-parent/flink-process-function-api/src/main/java/org/apache/flink/process/api/function/OneInputStreamProcessFunction.java
index c5860e06baccb..22de1e7b513cb 100644
--- a/flink-process-function-parent/flink-process-function-api/src/main/java/org/apache/flink/process/api/function/OneInputStreamProcessFunction.java
+++ b/flink-process-function-parent/flink-process-function-api/src/main/java/org/apache/flink/process/api/function/OneInputStreamProcessFunction.java
@@ -42,4 +42,13 @@ public interface OneInputStreamProcessFunction<IN, OUT> extends ProcessFunction
      * @param ctx, the context in which this function is executed.
      */
     default void endInput(NonPartitionedContext<OUT> ctx) {}
+
+    /**
+     * Callback for processing timer.
+     *
+     * @param timestamp when this callback is triggered.
+     * @param output to emit record.
+     * @param ctx, runtime context in which this function is executed.
+     */
+    default void onProcessingTimer(long timestamp, Collector<OUT> output, RuntimeContext ctx) {}
 }
diff --git a/flink-process-function-parent/flink-process-function-api/src/main/java/org/apache/flink/process/api/function/TwoInputBroadcastStreamProcessFunction.java b/flink-process-function-parent/flink-process-function-api/src/main/java/org/apache/flink/process/api/function/TwoInputBroadcastStreamProcessFunction.java
index 1ad3da28e70f5..b0388a75ec1ec 100644
--- a/flink-process-function-parent/flink-process-function-api/src/main/java/org/apache/flink/process/api/function/TwoInputBroadcastStreamProcessFunction.java
+++ b/flink-process-function-parent/flink-process-function-api/src/main/java/org/apache/flink/process/api/function/TwoInputBroadcastStreamProcessFunction.java
@@ -65,4 +65,13 @@ default void endNonBroadcastInput(NonPartitionedContext<OUT> ctx) {}
      * @param ctx, the context in which this function is executed.
      */
     default void endBroadcastInput(NonPartitionedContext<OUT> ctx) {}
+
+    /**
+     * Callback for processing timer.
+     *
+     * @param timestamp when this callback is triggered.
+     * @param output to emit record.
+     * @param ctx, runtime context in which this function is executed.
+     */
+    default void onProcessingTimer(long timestamp, Collector<OUT> output, RuntimeContext ctx) {}
 }
diff --git a/flink-process-function-parent/flink-process-function-api/src/main/java/org/apache/flink/process/api/function/TwoInputNonBroadcastStreamProcessFunction.java b/flink-process-function-parent/flink-process-function-api/src/main/java/org/apache/flink/process/api/function/TwoInputNonBroadcastStreamProcessFunction.java
index 19e2a2ba78701..d0d80392ef764 100644
--- a/flink-process-function-parent/flink-process-function-api/src/main/java/org/apache/flink/process/api/function/TwoInputNonBroadcastStreamProcessFunction.java
+++ b/flink-process-function-parent/flink-process-function-api/src/main/java/org/apache/flink/process/api/function/TwoInputNonBroadcastStreamProcessFunction.java
@@ -61,4 +61,13 @@ default void endFirstInput(NonPartitionedContext<OUT> ctx) {}
      * @param ctx, the context in which this function is executed.
      */
     default void endSecondInput(NonPartitionedContext<OUT> ctx) {}
+
+    /**
+     * Callback for processing timer.
+     *
+     * @param timestamp when this callback is triggered.
+     * @param output to emit record.
+     * @param ctx, runtime context in which this function is executed.
+     */
+    default void onProcessingTimer(long timestamp, Collector<OUT> output, RuntimeContext ctx) {}
 }
diff --git a/flink-process-function-parent/flink-process-function-api/src/main/java/org/apache/flink/process/api/function/TwoOutputStreamProcessFunction.java b/flink-process-function-parent/flink-process-function-api/src/main/java/org/apache/flink/process/api/function/TwoOutputStreamProcessFunction.java
index b26ca5bab6e8c..e4c5afd9545bb 100644
--- a/flink-process-function-parent/flink-process-function-api/src/main/java/org/apache/flink/process/api/function/TwoOutputStreamProcessFunction.java
+++ b/flink-process-function-parent/flink-process-function-api/src/main/java/org/apache/flink/process/api/function/TwoOutputStreamProcessFunction.java
@@ -45,4 +45,15 @@ void processRecord(
      * @param ctx, the context in which this function is executed.
      */
     default void endInput(TwoOutputNonPartitionedContext<OUT1, OUT2> ctx) {}
+
+    /**
+     * Callback for processing timer.
+     *
+     * @param timestamp when this callback is triggered.
+     * @param output1 to emit record.
+     * @param output2 to emit record.
+     * @param ctx, runtime context in which this function is executed.
+     */
+    default void onProcessingTimer(
+            long timestamp, Collector<OUT1> output1, Collector<OUT2> output2, RuntimeContext ctx) {}
 }
diff --git a/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/context/DefaultNonPartitionedContext.java b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/context/DefaultNonPartitionedContext.java
index 63ab902fddcb9..3f247f1cd51bf 100644
--- a/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/context/DefaultNonPartitionedContext.java
+++ b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/context/DefaultNonPartitionedContext.java
@@ -20,6 +20,7 @@
 
 import org.apache.flink.process.api.context.JobInfo;
 import org.apache.flink.process.api.context.NonPartitionedContext;
+import org.apache.flink.process.api.context.ProcessingTimeManager;
 import org.apache.flink.process.api.context.StateManager;
 import org.apache.flink.process.api.context.TaskInfo;
 import org.apache.flink.process.api.function.ApplyPartitionFunction;
@@ -52,4 +53,10 @@ public StateManager getStateManager() {
         // state is partition-aware, so it's always empty in non-partitioned context.
         return EmptyStateManager.INSTANCE;
     }
+
+    @Override
+    public ProcessingTimeManager getProcessingTimeManager() {
+        // processing timer is partition-aware, so it's not supported in non-partitioned context.
+        return UnsupportedProcessingTimeManager.INSTANCE;
+    }
 }
diff --git a/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/context/DefaultProcessingTimeManager.java b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/context/DefaultProcessingTimeManager.java
new file mode 100644
index 0000000000000..8844898f51fc8
--- /dev/null
+++ b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/context/DefaultProcessingTimeManager.java
@@ -0,0 +1,47 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.flink.process.impl.context;
+
+import org.apache.flink.process.api.context.ProcessingTimeManager;
+import org.apache.flink.runtime.state.VoidNamespace;
+import org.apache.flink.streaming.api.operators.InternalTimerService;
+
+/** The default implementation of {@link ProcessingTimeManager}. */
+public class DefaultProcessingTimeManager implements ProcessingTimeManager {
+    private final InternalTimerService<VoidNamespace> timerService;
+
+    public DefaultProcessingTimeManager(InternalTimerService<VoidNamespace> timerService) {
+        this.timerService = timerService;
+    }
+
+    @Override
+    public void registerProcessingTimer(long timestamp) {
+        timerService.registerProcessingTimeTimer(VoidNamespace.INSTANCE, timestamp);
+    }
+
+    @Override
+    public void deleteProcessingTimeTimer(long timestamp) {
+        timerService.deleteProcessingTimeTimer(VoidNamespace.INSTANCE, timestamp);
+    }
+
+    @Override
+    public long currentProcessingTime() {
+        return timerService.currentProcessingTime();
+    }
+}
diff --git a/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/context/DefaultRuntimeContext.java b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/context/DefaultRuntimeContext.java
index 71e186b334d44..d825935833401 100644
--- a/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/context/DefaultRuntimeContext.java
+++ b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/context/DefaultRuntimeContext.java
@@ -19,6 +19,7 @@
 package org.apache.flink.process.impl.context;
 
 import org.apache.flink.process.api.context.JobInfo;
+import org.apache.flink.process.api.context.ProcessingTimeManager;
 import org.apache.flink.process.api.context.RuntimeContext;
 import org.apache.flink.process.api.context.TaskInfo;
 import org.apache.flink.streaming.api.operators.StreamingRuntimeContext;
@@ -34,15 +35,19 @@ public class DefaultRuntimeContext implements RuntimeContext {
 
     private final DefaultStateManager stateManager;
 
+    private final ProcessingTimeManager processingTimeManager;
+
     public DefaultRuntimeContext(
             StreamingRuntimeContext operatorContext,
             int parallelism,
             int maxParallelism,
             String taskName,
-            Supplier<Optional<Object>> currentKeySupplier) {
+            Supplier<Optional<Object>> currentKeySupplier,
+            ProcessingTimeManager processingTimeManager) {
         this.jobInfo = new DefaultJobInfo(operatorContext);
         this.taskInfo = new DefaultTaskInfo(parallelism, maxParallelism, taskName);
         this.stateManager = new DefaultStateManager(currentKeySupplier);
+        this.processingTimeManager = processingTimeManager;
     }
 
     @Override
@@ -59,4 +64,8 @@ public TaskInfo getTaskInfo() {
     public DefaultStateManager getStateManager() {
         return stateManager;
     }
+
+    public ProcessingTimeManager getProcessingTimeManager() {
+        return processingTimeManager;
+    }
 }
diff --git a/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/context/DefaultTwoOutputNonPartitionedContext.java b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/context/DefaultTwoOutputNonPartitionedContext.java
index 1f05461226a77..4ed475069694b 100644
--- a/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/context/DefaultTwoOutputNonPartitionedContext.java
+++ b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/context/DefaultTwoOutputNonPartitionedContext.java
@@ -19,6 +19,7 @@
 package org.apache.flink.process.impl.context;
 
 import org.apache.flink.process.api.context.JobInfo;
+import org.apache.flink.process.api.context.ProcessingTimeManager;
 import org.apache.flink.process.api.context.StateManager;
 import org.apache.flink.process.api.context.TaskInfo;
 import org.apache.flink.process.api.context.TwoOutputNonPartitionedContext;
@@ -52,4 +53,10 @@ public StateManager getStateManager() {
         // state is partition-aware, so it's always empty in non-partitioned context.
         return EmptyStateManager.INSTANCE;
     }
+
+    @Override
+    public ProcessingTimeManager getProcessingTimeManager() {
+        // processing timer is partition-aware, so it's not supported in non-partitioned context.
+        return UnsupportedProcessingTimeManager.INSTANCE;
+    }
 }
diff --git a/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/context/UnsupportedProcessingTimeManager.java b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/context/UnsupportedProcessingTimeManager.java
new file mode 100644
index 0000000000000..91f9e2cfb2c78
--- /dev/null
+++ b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/context/UnsupportedProcessingTimeManager.java
@@ -0,0 +1,50 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.flink.process.impl.context;
+
+import org.apache.flink.process.api.context.ProcessingTimeManager;
+
+/**
+ * The special implementation of {@link ProcessingTimeManager}, all its methods are not supported.
+ * This is used for context that can not define the key.
+ */
+public class UnsupportedProcessingTimeManager implements ProcessingTimeManager {
+    public static UnsupportedProcessingTimeManager INSTANCE =
+            new UnsupportedProcessingTimeManager();
+
+    private UnsupportedProcessingTimeManager() {}
+
+    @Override
+    public void registerProcessingTimer(long timestamp) {
+        throw new UnsupportedOperationException(
+                "Register processing timer is unsupported in current context.");
+    }
+
+    @Override
+    public void deleteProcessingTimeTimer(long timestamp) {
+        throw new UnsupportedOperationException(
+                "Delete processing timer is unsupported in current context.");
+    }
+
+    @Override
+    public long currentProcessingTime() {
+        throw new UnsupportedOperationException(
+                "Get current processing time is unsupported in current context.");
+    }
+}
diff --git a/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/KeyedProcessOperator.java b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/KeyedProcessOperator.java
index 44888a063b9f7..b6095caecfd78 100644
--- a/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/KeyedProcessOperator.java
+++ b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/KeyedProcessOperator.java
@@ -19,18 +19,27 @@
 package org.apache.flink.process.impl.operators;
 
 import org.apache.flink.api.java.functions.KeySelector;
+import org.apache.flink.process.api.context.ProcessingTimeManager;
 import org.apache.flink.process.api.function.OneInputStreamProcessFunction;
 import org.apache.flink.process.api.stream.KeyedPartitionStream;
 import org.apache.flink.process.impl.common.KeyCheckedOutputCollector;
 import org.apache.flink.process.impl.common.OutputCollector;
 import org.apache.flink.process.impl.common.TimestampCollector;
+import org.apache.flink.process.impl.context.DefaultProcessingTimeManager;
+import org.apache.flink.runtime.state.VoidNamespace;
+import org.apache.flink.runtime.state.VoidNamespaceSerializer;
+import org.apache.flink.streaming.api.operators.InternalTimer;
+import org.apache.flink.streaming.api.operators.InternalTimerService;
+import org.apache.flink.streaming.api.operators.Triggerable;
 
 import javax.annotation.Nullable;
 
 import java.util.Optional;
 
 /** Operator for {@link OneInputStreamProcessFunction} in {@link KeyedPartitionStream}. */
-public class KeyedProcessOperator<KEY, IN, OUT> extends ProcessOperator<IN, OUT> {
+public class KeyedProcessOperator<KEY, IN, OUT> extends ProcessOperator<IN, OUT>
+        implements Triggerable<KEY, VoidNamespace> {
+    private transient InternalTimerService<VoidNamespace> timerService;
 
     @Nullable private final KeySelector<OUT, KEY> outKeySelector;
 
@@ -45,6 +54,13 @@ public KeyedProcessOperator(
         this.outKeySelector = outKeySelector;
     }
 
+    @Override
+    public void open() throws Exception {
+        this.timerService =
+                getInternalTimerService("processing timer", VoidNamespaceSerializer.INSTANCE, this);
+        super.open();
+    }
+
     @Override
     protected TimestampCollector<OUT> getOutputCollector() {
         return outKeySelector != null
@@ -57,4 +73,22 @@ protected TimestampCollector<OUT> getOutputCollector() {
     protected Optional<Object> currentKey() {
         return Optional.ofNullable(getCurrentKey());
     }
+
+    @Override
+    public void onEventTime(InternalTimer<KEY, VoidNamespace> timer) throws Exception {
+        // do nothing at the moment.
+    }
+
+    @Override
+    public void onProcessingTime(InternalTimer<KEY, VoidNamespace> timer) throws Exception {
+        // align the key context with the registered timer.
+        context.getStateManager().setCurrentKey(timer.getKey());
+        userFunction.onProcessingTimer(timer.getTimestamp(), getOutputCollector(), context);
+        context.getStateManager().resetCurrentKey();
+    }
+
+    @Override
+    protected ProcessingTimeManager getProcessingTimeManager() {
+        return new DefaultProcessingTimeManager(timerService);
+    }
 }
diff --git a/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/KeyedTwoInputBroadcastProcessOperator.java b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/KeyedTwoInputBroadcastProcessOperator.java
index bed6029a1a385..1ba91b86c696f 100644
--- a/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/KeyedTwoInputBroadcastProcessOperator.java
+++ b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/KeyedTwoInputBroadcastProcessOperator.java
@@ -19,11 +19,18 @@
 package org.apache.flink.process.impl.operators;
 
 import org.apache.flink.api.java.functions.KeySelector;
+import org.apache.flink.process.api.context.ProcessingTimeManager;
 import org.apache.flink.process.api.function.TwoInputBroadcastStreamProcessFunction;
 import org.apache.flink.process.api.stream.KeyedPartitionStream;
 import org.apache.flink.process.impl.common.KeyCheckedOutputCollector;
 import org.apache.flink.process.impl.common.OutputCollector;
 import org.apache.flink.process.impl.common.TimestampCollector;
+import org.apache.flink.process.impl.context.DefaultProcessingTimeManager;
+import org.apache.flink.runtime.state.VoidNamespace;
+import org.apache.flink.runtime.state.VoidNamespaceSerializer;
+import org.apache.flink.streaming.api.operators.InternalTimer;
+import org.apache.flink.streaming.api.operators.InternalTimerService;
+import org.apache.flink.streaming.api.operators.Triggerable;
 
 import javax.annotation.Nullable;
 
@@ -31,7 +38,10 @@
 
 /** Operator for {@link TwoInputBroadcastStreamProcessFunction} in {@link KeyedPartitionStream}. */
 public class KeyedTwoInputBroadcastProcessOperator<KEY, IN1, IN2, OUT>
-        extends TwoInputBroadcastProcessOperator<IN1, IN2, OUT> {
+        extends TwoInputBroadcastProcessOperator<IN1, IN2, OUT>
+        implements Triggerable<KEY, VoidNamespace> {
+    private transient InternalTimerService<VoidNamespace> timerService;
+
     @Nullable private final KeySelector<OUT, KEY> outKeySelector;
 
     public KeyedTwoInputBroadcastProcessOperator(
@@ -46,6 +56,13 @@ public KeyedTwoInputBroadcastProcessOperator(
         this.outKeySelector = outKeySelector;
     }
 
+    @Override
+    public void open() throws Exception {
+        this.timerService =
+                getInternalTimerService("processing timer", VoidNamespaceSerializer.INSTANCE, this);
+        super.open();
+    }
+
     @Override
     protected TimestampCollector<OUT> getOutputCollector() {
         return outKeySelector == null
@@ -58,4 +75,21 @@ protected TimestampCollector<OUT> getOutputCollector() {
     protected Optional<Object> currentKey() {
         return Optional.ofNullable(getCurrentKey());
     }
+
+    protected ProcessingTimeManager getProcessingTimeManager() {
+        return new DefaultProcessingTimeManager(timerService);
+    }
+
+    @Override
+    public void onEventTime(InternalTimer<KEY, VoidNamespace> timer) throws Exception {
+        // do nothing at the moment.
+    }
+
+    @Override
+    public void onProcessingTime(InternalTimer<KEY, VoidNamespace> timer) throws Exception {
+        // align the key context with the registered timer.
+        context.getStateManager().setCurrentKey(timer.getKey());
+        userFunction.onProcessingTimer(timer.getTimestamp(), getOutputCollector(), context);
+        context.getStateManager().resetCurrentKey();
+    }
 }
diff --git a/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/KeyedTwoInputNonBroadcastProcessOperator.java b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/KeyedTwoInputNonBroadcastProcessOperator.java
index bb7acf4f02df1..9600bb0e498d6 100644
--- a/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/KeyedTwoInputNonBroadcastProcessOperator.java
+++ b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/KeyedTwoInputNonBroadcastProcessOperator.java
@@ -19,11 +19,18 @@
 package org.apache.flink.process.impl.operators;
 
 import org.apache.flink.api.java.functions.KeySelector;
+import org.apache.flink.process.api.context.ProcessingTimeManager;
 import org.apache.flink.process.api.function.TwoInputNonBroadcastStreamProcessFunction;
 import org.apache.flink.process.api.stream.KeyedPartitionStream;
 import org.apache.flink.process.impl.common.KeyCheckedOutputCollector;
 import org.apache.flink.process.impl.common.OutputCollector;
 import org.apache.flink.process.impl.common.TimestampCollector;
+import org.apache.flink.process.impl.context.DefaultProcessingTimeManager;
+import org.apache.flink.runtime.state.VoidNamespace;
+import org.apache.flink.runtime.state.VoidNamespaceSerializer;
+import org.apache.flink.streaming.api.operators.InternalTimer;
+import org.apache.flink.streaming.api.operators.InternalTimerService;
+import org.apache.flink.streaming.api.operators.Triggerable;
 
 import javax.annotation.Nullable;
 
@@ -33,7 +40,10 @@
  * Operator for {@link TwoInputNonBroadcastStreamProcessFunction} in {@link KeyedPartitionStream}.
  */
 public class KeyedTwoInputNonBroadcastProcessOperator<KEY, IN1, IN2, OUT>
-        extends TwoInputNonBroadcastProcessOperator<IN1, IN2, OUT> {
+        extends TwoInputNonBroadcastProcessOperator<IN1, IN2, OUT>
+        implements Triggerable<KEY, VoidNamespace> {
+    private transient InternalTimerService<VoidNamespace> timerService;
+
     @Nullable private final KeySelector<OUT, KEY> outKeySelector;
 
     public KeyedTwoInputNonBroadcastProcessOperator(
@@ -48,6 +58,13 @@ public KeyedTwoInputNonBroadcastProcessOperator(
         this.outKeySelector = outKeySelector;
     }
 
+    @Override
+    public void open() throws Exception {
+        this.timerService =
+                getInternalTimerService("processing timer", VoidNamespaceSerializer.INSTANCE, this);
+        super.open();
+    }
+
     @Override
     protected TimestampCollector<OUT> getOutputCollector() {
         return outKeySelector == null
@@ -60,4 +77,21 @@ protected TimestampCollector<OUT> getOutputCollector() {
     protected Optional<Object> currentKey() {
         return Optional.ofNullable(getCurrentKey());
     }
+
+    protected ProcessingTimeManager getProcessingTimeManager() {
+        return new DefaultProcessingTimeManager(timerService);
+    }
+
+    @Override
+    public void onEventTime(InternalTimer<KEY, VoidNamespace> timer) throws Exception {
+        // do nothing at the moment.
+    }
+
+    @Override
+    public void onProcessingTime(InternalTimer<KEY, VoidNamespace> timer) throws Exception {
+        // align the key context with the registered timer.
+        context.getStateManager().setCurrentKey(timer.getKey());
+        userFunction.onProcessingTimer(timer.getTimestamp(), getOutputCollector(), context);
+        context.getStateManager().resetCurrentKey();
+    }
 }
diff --git a/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/KeyedTwoOutputProcessOperator.java b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/KeyedTwoOutputProcessOperator.java
index 702899e877446..9b2cf0c4319a5 100644
--- a/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/KeyedTwoOutputProcessOperator.java
+++ b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/KeyedTwoOutputProcessOperator.java
@@ -19,9 +19,16 @@
 package org.apache.flink.process.impl.operators;
 
 import org.apache.flink.api.java.functions.KeySelector;
+import org.apache.flink.process.api.context.ProcessingTimeManager;
 import org.apache.flink.process.api.function.TwoOutputStreamProcessFunction;
 import org.apache.flink.process.impl.common.OutputCollector;
 import org.apache.flink.process.impl.common.TimestampCollector;
+import org.apache.flink.process.impl.context.DefaultProcessingTimeManager;
+import org.apache.flink.runtime.state.VoidNamespace;
+import org.apache.flink.runtime.state.VoidNamespaceSerializer;
+import org.apache.flink.streaming.api.operators.InternalTimer;
+import org.apache.flink.streaming.api.operators.InternalTimerService;
+import org.apache.flink.streaming.api.operators.Triggerable;
 import org.apache.flink.util.ExceptionUtils;
 import org.apache.flink.util.OutputTag;
 
@@ -31,7 +38,10 @@
 
 /** */
 public class KeyedTwoOutputProcessOperator<KEY, IN, OUT_MAIN, OUT_SIDE>
-        extends TwoOutputProcessOperator<IN, OUT_MAIN, OUT_SIDE> {
+        extends TwoOutputProcessOperator<IN, OUT_MAIN, OUT_SIDE>
+        implements Triggerable<KEY, VoidNamespace> {
+
+    private transient InternalTimerService<VoidNamespace> timerService;
 
     @Nullable private final KeySelector<OUT_MAIN, KEY> mainOutKeySelector;
 
@@ -53,6 +63,13 @@ public KeyedTwoOutputProcessOperator(
         this.sideOutKeySelector = sideOutKeySelector;
     }
 
+    @Override
+    public void open() throws Exception {
+        this.timerService =
+                getInternalTimerService("processing timer", VoidNamespaceSerializer.INSTANCE, this);
+        super.open();
+    }
+
     @Override
     protected TimestampCollector<OUT_MAIN> getMainCollector() {
         return mainOutKeySelector != null && sideOutKeySelector != null
@@ -73,6 +90,24 @@ protected Optional<Object> currentKey() {
         return Optional.ofNullable(getCurrentKey());
     }
 
+    protected ProcessingTimeManager getProcessingTimeManager() {
+        return new DefaultProcessingTimeManager(timerService);
+    }
+
+    @Override
+    public void onEventTime(InternalTimer<KEY, VoidNamespace> timer) throws Exception {
+        // do nothing at the moment.
+    }
+
+    @Override
+    public void onProcessingTime(InternalTimer<KEY, VoidNamespace> timer) throws Exception {
+        // align the key context with the registered timer.
+        context.getStateManager().setCurrentKey(timer.getKey());
+        userFunction.onProcessingTimer(
+                timer.getTimestamp(), getMainCollector(), getSideCollector(), context);
+        context.getStateManager().resetCurrentKey();
+    }
+
     private class KeyCheckedOutputCollector<T> extends TimestampCollector<T> {
 
         private final TimestampCollector<T> outputCollector;
diff --git a/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/ProcessOperator.java b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/ProcessOperator.java
index 5e5e496137e47..14ad500f93514 100644
--- a/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/ProcessOperator.java
+++ b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/ProcessOperator.java
@@ -19,11 +19,13 @@
 package org.apache.flink.process.impl.operators;
 
 import org.apache.flink.api.common.TaskInfo;
+import org.apache.flink.process.api.context.ProcessingTimeManager;
 import org.apache.flink.process.api.function.OneInputStreamProcessFunction;
 import org.apache.flink.process.impl.common.OutputCollector;
 import org.apache.flink.process.impl.common.TimestampCollector;
 import org.apache.flink.process.impl.context.DefaultNonPartitionedContext;
 import org.apache.flink.process.impl.context.DefaultRuntimeContext;
+import org.apache.flink.process.impl.context.UnsupportedProcessingTimeManager;
 import org.apache.flink.streaming.api.operators.AbstractUdfStreamOperator;
 import org.apache.flink.streaming.api.operators.BoundedOneInput;
 import org.apache.flink.streaming.api.operators.ChainingStrategy;
@@ -61,7 +63,8 @@ public void open() throws Exception {
                         taskInfo.getNumberOfParallelSubtasks(),
                         taskInfo.getMaxNumberOfParallelSubtasks(),
                         taskInfo.getTaskName(),
-                        this::currentKey);
+                        this::currentKey,
+                        getProcessingTimeManager());
         nonPartitionedContext = new DefaultNonPartitionedContext<>(context);
         outputCollector = getOutputCollector();
     }
@@ -85,4 +88,8 @@ protected Optional<Object> currentKey() {
         // non-keyed operator always return empty key.
         return Optional.empty();
     }
+
+    protected ProcessingTimeManager getProcessingTimeManager() {
+        return UnsupportedProcessingTimeManager.INSTANCE;
+    }
 }
diff --git a/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/TwoInputBroadcastProcessOperator.java b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/TwoInputBroadcastProcessOperator.java
index e2a9bf22dd9b2..da7f5dc265f3e 100644
--- a/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/TwoInputBroadcastProcessOperator.java
+++ b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/TwoInputBroadcastProcessOperator.java
@@ -19,11 +19,13 @@
 package org.apache.flink.process.impl.operators;
 
 import org.apache.flink.api.common.TaskInfo;
+import org.apache.flink.process.api.context.ProcessingTimeManager;
 import org.apache.flink.process.api.function.TwoInputBroadcastStreamProcessFunction;
 import org.apache.flink.process.impl.common.OutputCollector;
 import org.apache.flink.process.impl.common.TimestampCollector;
 import org.apache.flink.process.impl.context.DefaultNonPartitionedContext;
 import org.apache.flink.process.impl.context.DefaultRuntimeContext;
+import org.apache.flink.process.impl.context.UnsupportedProcessingTimeManager;
 import org.apache.flink.streaming.api.operators.AbstractUdfStreamOperator;
 import org.apache.flink.streaming.api.operators.BoundedMultiInput;
 import org.apache.flink.streaming.api.operators.ChainingStrategy;
@@ -65,7 +67,8 @@ public void open() throws Exception {
                         taskInfo.getNumberOfParallelSubtasks(),
                         taskInfo.getMaxNumberOfParallelSubtasks(),
                         taskInfo.getTaskName(),
-                        this::currentKey);
+                        this::currentKey,
+                        getProcessingTimeManager());
         this.nonPartitionedContext = new DefaultNonPartitionedContext<>(context);
     }
 
@@ -100,4 +103,8 @@ protected Optional<Object> currentKey() {
         // non-keyed operator always return empty key.
         return Optional.empty();
     }
+
+    protected ProcessingTimeManager getProcessingTimeManager() {
+        return UnsupportedProcessingTimeManager.INSTANCE;
+    }
 }
diff --git a/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/TwoInputNonBroadcastProcessOperator.java b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/TwoInputNonBroadcastProcessOperator.java
index 9352143aa0022..11f2e32722f8a 100644
--- a/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/TwoInputNonBroadcastProcessOperator.java
+++ b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/TwoInputNonBroadcastProcessOperator.java
@@ -19,11 +19,13 @@
 package org.apache.flink.process.impl.operators;
 
 import org.apache.flink.api.common.TaskInfo;
+import org.apache.flink.process.api.context.ProcessingTimeManager;
 import org.apache.flink.process.api.function.TwoInputNonBroadcastStreamProcessFunction;
 import org.apache.flink.process.impl.common.OutputCollector;
 import org.apache.flink.process.impl.common.TimestampCollector;
 import org.apache.flink.process.impl.context.DefaultNonPartitionedContext;
 import org.apache.flink.process.impl.context.DefaultRuntimeContext;
+import org.apache.flink.process.impl.context.UnsupportedProcessingTimeManager;
 import org.apache.flink.streaming.api.operators.AbstractUdfStreamOperator;
 import org.apache.flink.streaming.api.operators.BoundedMultiInput;
 import org.apache.flink.streaming.api.operators.ChainingStrategy;
@@ -65,7 +67,8 @@ public void open() throws Exception {
                         taskInfo.getNumberOfParallelSubtasks(),
                         taskInfo.getMaxNumberOfParallelSubtasks(),
                         taskInfo.getTaskName(),
-                        this::currentKey);
+                        this::currentKey,
+                        getProcessingTimeManager());
         this.nonPartitionedContext = new DefaultNonPartitionedContext<>(context);
     }
 
@@ -100,4 +103,8 @@ protected Optional<Object> currentKey() {
         // non-keyed operator always return empty key.
         return Optional.empty();
     }
+
+    protected ProcessingTimeManager getProcessingTimeManager() {
+        return UnsupportedProcessingTimeManager.INSTANCE;
+    }
 }
diff --git a/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/TwoOutputProcessOperator.java b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/TwoOutputProcessOperator.java
index a864d08a06164..82b10b7073a52 100644
--- a/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/TwoOutputProcessOperator.java
+++ b/flink-process-function-parent/flink-process-function/src/main/java/org/apache/flink/process/impl/operators/TwoOutputProcessOperator.java
@@ -19,12 +19,14 @@
 package org.apache.flink.process.impl.operators;
 
 import org.apache.flink.api.common.TaskInfo;
+import org.apache.flink.process.api.context.ProcessingTimeManager;
 import org.apache.flink.process.api.context.TwoOutputNonPartitionedContext;
 import org.apache.flink.process.api.function.TwoOutputStreamProcessFunction;
 import org.apache.flink.process.impl.common.OutputCollector;
 import org.apache.flink.process.impl.common.TimestampCollector;
 import org.apache.flink.process.impl.context.DefaultRuntimeContext;
 import org.apache.flink.process.impl.context.DefaultTwoOutputNonPartitionedContext;
+import org.apache.flink.process.impl.context.UnsupportedProcessingTimeManager;
 import org.apache.flink.streaming.api.operators.AbstractUdfStreamOperator;
 import org.apache.flink.streaming.api.operators.BoundedOneInput;
 import org.apache.flink.streaming.api.operators.ChainingStrategy;
@@ -76,7 +78,8 @@ public void open() throws Exception {
                         taskInfo.getNumberOfParallelSubtasks(),
                         taskInfo.getMaxNumberOfParallelSubtasks(),
                         taskInfo.getTaskName(),
-                        this::currentKey);
+                        this::currentKey,
+                        getProcessingTimeManager());
         this.nonPartitionedContext = new DefaultTwoOutputNonPartitionedContext<>(context);
     }
 
@@ -105,6 +108,10 @@ protected Optional<Object> currentKey() {
         return Optional.empty();
     }
 
+    protected ProcessingTimeManager getProcessingTimeManager() {
+        return UnsupportedProcessingTimeManager.INSTANCE;
+    }
+
     /**
      * This is a special implementation of {@link TimestampCollector} that using side-output
      * mechanism to emit data.