diff --git a/protobuf-kotlin-serialization/src/commonMain/kotlin/pro/felixo/protobuf/serialization/generation/internal/Common.kt b/protobuf-kotlin-serialization/src/commonMain/kotlin/pro/felixo/protobuf/serialization/generation/internal/Common.kt
index f9d00ca..9804d0c 100644
--- a/protobuf-kotlin-serialization/src/commonMain/kotlin/pro/felixo/protobuf/serialization/generation/internal/Common.kt
+++ b/protobuf-kotlin-serialization/src/commonMain/kotlin/pro/felixo/protobuf/serialization/generation/internal/Common.kt
@@ -34,15 +34,16 @@ fun TypeContext.field(
     name: Identifier,
     number: FieldNumber,
     annotations: List<Annotation>,
-    descriptor: SerialDescriptor
+    descriptor: SerialDescriptor,
+    forceEncodeZeroValue: Boolean = false
 ): Field {
     val typeDescriptor = descriptor.actual
     val nullable = descriptor.isNullable || typeDescriptor.isNullable
     return when (val kind = typeDescriptor.kind) {
         is PrimitiveKind ->
-            field(name, scalar(annotations, kind), number, nullable)
+            field(name, scalar(annotations, kind), number, nullable, forceEncodeZeroValue)
         StructureKind.CLASS, StructureKind.OBJECT, SerialKind.ENUM, is PolymorphicKind ->
-            field(name, root.namedType(typeDescriptor), number, nullable)
+            field(name, root.namedType(typeDescriptor), number, nullable, forceEncodeZeroValue)
         SerialKind.CONTEXTUAL ->
             field(
                 name,
@@ -53,7 +54,7 @@ fun TypeContext.field(
             )
         StructureKind.LIST ->
             if (typeDescriptor.getElementDescriptor(0).kind == PrimitiveKind.BYTE)
-                field(name, FieldEncoding.Bytes, number, nullable)
+                field(name, FieldEncoding.Bytes, number, nullable, forceEncodeZeroValue)
             else if (nullable)
                 optionalListField(typeDescriptor, name, number, annotations)
             else
@@ -70,12 +71,13 @@ private fun TypeContext.field(
     name: Identifier,
     type: FieldEncoding,
     number: FieldNumber,
-    optional: Boolean
+    optional: Boolean,
+    encodeZeroValue: Boolean
 ): Field = Field(
     name,
     type,
     number,
     if (optional) FieldRule.Optional else FieldRule.Singular,
-    fieldEncoder(type, number, optional),
+    fieldEncoder(type, number, encodeZeroValue || optional),
     fieldDecoder(type)
 )
diff --git a/protobuf-kotlin-serialization/src/commonMain/kotlin/pro/felixo/protobuf/serialization/generation/internal/Polymorphic.kt b/protobuf-kotlin-serialization/src/commonMain/kotlin/pro/felixo/protobuf/serialization/generation/internal/Polymorphic.kt
index 2ae5ba8..72a858a 100644
--- a/protobuf-kotlin-serialization/src/commonMain/kotlin/pro/felixo/protobuf/serialization/generation/internal/Polymorphic.kt
+++ b/protobuf-kotlin-serialization/src/commonMain/kotlin/pro/felixo/protobuf/serialization/generation/internal/Polymorphic.kt
@@ -60,30 +60,24 @@ private fun TypeContext.messageOfPolymorphicClass(
     }
 }
 
-private fun TypeContext.fieldForSubType(subDescriptor: SerialDescriptor, numberIterator: FieldNumberIterator): Field {
-    val subTypeRef = root.namedType(subDescriptor)
-    val number = FieldNumber(
-        subDescriptor.annotations.filterIsInstance<ProtoNumber>()
-            .firstOrNull()?.number
-            ?: numberIterator.next()
-    )
-    return Field(
-        Identifier(
-            subTypeRef.name.value.replaceFirstChar { it.lowercaseChar() }
+private fun TypeContext.fieldForSubType(subDescriptor: SerialDescriptor, numberIterator: FieldNumberIterator): Field =
+    field(
+        Identifier(simpleTypeName(subDescriptor).replaceFirstChar { it.lowercaseChar() }),
+        FieldNumber(
+            subDescriptor.annotations.filterIsInstance<ProtoNumber>()
+                .firstOrNull()?.number
+                ?: numberIterator.next()
         ),
-        subTypeRef,
-        number,
-        encoder = fieldEncoder(subTypeRef, number, true),
-        decoder = fieldDecoder(subTypeRef)
+        emptyList(),
+        subDescriptor,
+        forceEncodeZeroValue = true
     )
-}
 
-private fun fieldNumberIteratorFromSubTypes(descriptors: Iterable<SerialDescriptor>): FieldNumberIterator {
-    return FieldNumberIterator(
+private fun fieldNumberIteratorFromSubTypes(descriptors: Iterable<SerialDescriptor>): FieldNumberIterator =
+    FieldNumberIterator(
         descriptors.mapNotNull {
             it.annotations.filterIsInstance<ProtoNumber>().firstOrNull()?.number
         }.requireNoDuplicates { duplicatedNumber ->
             "Duplicate field number $duplicatedNumber in sub-types: ${descriptors.map { it.serialName }}"
         }
     )
-}
diff --git a/protobuf-kotlin-serialization/src/commonTest/kotlin/pro/felixo/protobuf/serialization/integrationtests/InlineIntegrationTest.kt b/protobuf-kotlin-serialization/src/commonTest/kotlin/pro/felixo/protobuf/serialization/integrationtests/InlineIntegrationTest.kt
index 9961959..e51c36b 100644
--- a/protobuf-kotlin-serialization/src/commonTest/kotlin/pro/felixo/protobuf/serialization/integrationtests/InlineIntegrationTest.kt
+++ b/protobuf-kotlin-serialization/src/commonTest/kotlin/pro/felixo/protobuf/serialization/integrationtests/InlineIntegrationTest.kt
@@ -320,6 +320,52 @@ class InlineIntegrationTest : StringSpec({
             )
         }
 
+        "creates class hierarchy with value sub-class" {
+            givenSchema(
+                SuperClass.serializer().descriptor,
+                encodeZeroValues = true
+            )
+            verifySchema(
+                """
+                message SuperClass {
+                    oneof subtypes {
+                        int32 subValueClassWithInt = 1;
+                        string subValueClassWithString = 2;
+                    }
+                }
+                """
+            )
+            verifyConversion<SuperClass>(
+                SubValueClassWithInt(0),
+                "1: 0"
+            )
+            verifyConversion<SuperClass>(
+                SubValueClassWithInt(1),
+                "1: 1"
+            )
+            verifyConversion<SuperClass>(
+                SubValueClassWithString(""),
+                "2: {}"
+            )
+            verifyConversion<SuperClass>(
+                SubValueClassWithString("foo"),
+                """2: { "foo" }"""
+            )
+
+            givenSchema(
+                SuperClass.serializer().descriptor,
+                encodeZeroValues = false
+            )
+            verifyConversion<SuperClass>(
+                SubValueClassWithInt(0),
+                "1: 0"
+            )
+            verifyConversion<SuperClass>(
+                SubValueClassWithString(""),
+                "2: {}"
+            )
+        }
+
         "does not create synthetic top-level message from value class with custom serializer" {
             givenSchema(StringIntValueClass.serializer().descriptor)
             verifySchemaGenerationFails()
@@ -454,4 +500,17 @@ class InlineIntegrationTest : StringSpec({
 
         override fun serialize(encoder: Encoder, value: StringIntValueClass) = encoder.encodeString("${value.value}")
     }
+
+    @Serializable
+    sealed interface SuperClass
+
+    @JvmInline
+    @Serializable
+    @ProtoNumber(1)
+    value class SubValueClassWithInt(val int: Int) : SuperClass
+
+    @JvmInline
+    @Serializable
+    @ProtoNumber(2)
+    value class SubValueClassWithString(val string: String) : SuperClass
 }