diff --git a/.chronus/changes/python-usage-namespace-test-2026-5-26-23-18-25.md b/.chronus/changes/python-usage-namespace-test-2026-5-26-23-18-25.md
new file mode 100644
index 00000000000..255a67569a5
--- /dev/null
+++ b/.chronus/changes/python-usage-namespace-test-2026-5-26-23-18-25.md
@@ -0,0 +1,7 @@
+---
+changeKind: internal
+packages:
+  - "@typespec/http-client-python"
+---
+
+Add sync and async mock API tests for the Azure client-generator-core usage namespace usage scenario from azure-http-specs.
diff --git a/packages/http-client-python/tests/mock_api/azure/asynctests/test_azure_client_generator_core_usage_async.py b/packages/http-client-python/tests/mock_api/azure/asynctests/test_azure_client_generator_core_usage_async.py
index 816279eeb94..9a82c7e573a 100644
--- a/packages/http-client-python/tests/mock_api/azure/asynctests/test_azure_client_generator_core_usage_async.py
+++ b/packages/http-client-python/tests/mock_api/azure/asynctests/test_azure_client_generator_core_usage_async.py
@@ -37,3 +37,9 @@ async def test_orphan_model_serializable(client: UsageClient):
     await client.model_in_operation.orphan_model_serializable(
         body=models.OrphanModel(model_name="name", description="desc")
     )
+
+
+@pytest.mark.asyncio
+async def test_namespace_model_serializable(client: UsageClient):
+    namespace_model = models.NamespaceModel(name="test")
+    await client.namespace_usage.namespace_model_serializable(body=namespace_model)
diff --git a/packages/http-client-python/tests/mock_api/azure/test_azure_client_generator_core_usage.py b/packages/http-client-python/tests/mock_api/azure/test_azure_client_generator_core_usage.py
index 0094bef89a1..4bc9b912324 100644
--- a/packages/http-client-python/tests/mock_api/azure/test_azure_client_generator_core_usage.py
+++ b/packages/http-client-python/tests/mock_api/azure/test_azure_client_generator_core_usage.py
@@ -30,3 +30,8 @@ def test_model_usage(client: UsageClient):
 
 def test_orphan_model_serializable(client: UsageClient):
     client.model_in_operation.orphan_model_serializable(body=models.OrphanModel(model_name="name", description="desc"))
+
+
+def test_namespace_model_serializable(client: UsageClient):
+    namespace_model = models.NamespaceModel(name="test")
+    client.namespace_usage.namespace_model_serializable(body=namespace_model)