diff --git a/elasticsearch/_async/client/__init__.py b/elasticsearch/_async/client/__init__.py
index 84d1f3d4d..587a4c3e4 100644
--- a/elasticsearch/_async/client/__init__.py
+++ b/elasticsearch/_async/client/__init__.py
@@ -89,6 +89,8 @@
     client_node_configs,
     is_requests_http_auth,
     is_requests_node_class,
+    is_httpx_http_auth,
+    is_httpx_node_class,
 )
 from .watcher import WatcherClient
 from .xpack import XPackClient
@@ -244,6 +246,20 @@ def __init__(
                     requests_session_auth = http_auth
                     http_auth = DEFAULT
 
+                if is_httpx_http_auth(http_auth):
+                    # If we're using custom httpx authentication
+                    # then we need to alert the user that they also
+                    # need to use 'node_class=httpxasync'.
+                    if not is_httpx_node_class(node_class):
+                        raise ValueError(
+                            "Using a custom 'httpx.Auth' class for "
+                            "'http_auth' must be used with node_class='httpxasync'"
+                        )
+
+                    # Reset 'http_auth' to DEFAULT so it's not consumed below.
+                    requests_session_auth = http_auth
+                    http_auth = DEFAULT
+
             node_configs = client_node_configs(
                 hosts,
                 cloud_id=cloud_id,
diff --git a/elasticsearch/_async/client/utils.py b/elasticsearch/_async/client/utils.py
index 97918d9e4..aefc753de 100644
--- a/elasticsearch/_async/client/utils.py
+++ b/elasticsearch/_async/client/utils.py
@@ -15,6 +15,15 @@
 #  specific language governing permissions and limitations
 #  under the License.
 
+import inspect
+from typing import (
+    TYPE_CHECKING,
+    Any,
+)
+
+from elastic_transport import HttpxAsyncHttpNode
+from elastic_transport.client_utils import DEFAULT
+
 from ..._sync.client.utils import (
     _TYPE_ASYNC_SNIFF_CALLBACK,
     _TYPE_HOSTS,
@@ -31,6 +40,33 @@
     is_requests_node_class,
 )
 
+
+def is_httpx_http_auth(http_auth: Any) -> bool:
+    """Detect if an http_auth value is a custom Httpx auth object"""
+    try:
+        from httpx import Auth
+
+        return isinstance(http_auth, Auth)
+    except ImportError:
+        pass
+    return False
+
+
+def is_httpx_node_class(node_class: Any) -> bool:
+    """Detect if 'HttpxAsyncHttpNode' would be used given the setting of 'node_class'"""
+    return (
+        node_class is not None
+        and node_class is not DEFAULT
+        and (
+            node_class == "httpxasync"
+            or (
+                inspect.isclass(node_class)
+                and issubclass(node_class, HttpxAsyncHttpNode)
+            )
+        )
+    )
+
+
 __all__ = [
     "CLIENT_META_SERVICE",
     "_TYPE_ASYNC_SNIFF_CALLBACK",
@@ -45,4 +81,6 @@
     "_stability_warning",
     "is_requests_http_auth",
     "is_requests_node_class",
+    "is_httpx_http_auth",
+    "is_httpx_node_class",
 ]