diff --git a/.chronus/changes/azure-http-specs_client-namespace-2024-10-29-12-8-41.md b/.chronus/changes/azure-http-specs_client-namespace-2024-10-29-12-8-41.md
new file mode 100644
index 0000000000..8616a0116b
--- /dev/null
+++ b/.chronus/changes/azure-http-specs_client-namespace-2024-10-29-12-8-41.md
@@ -0,0 +1,7 @@
+---
+changeKind: feature
+packages:
+  - "@azure-tools/azure-http-specs"
+---
+
+Add test scenario for clientNamespace
\ No newline at end of file
diff --git a/packages/azure-http-specs/spec-summary.md b/packages/azure-http-specs/spec-summary.md
index 899eb39c5a..05c7a8e808 100644
--- a/packages/azure-http-specs/spec-summary.md
+++ b/packages/azure-http-specs/spec-summary.md
@@ -1717,6 +1717,23 @@ Expected header parameters:
   Expected response header:
 - x-ms-client-request-id=<uuid string same with request header>
 
+### Client_ClientNamespace
+
+- Endpoints:
+  - `get /client/client-namespace/second`
+  - `get /client/client-namespace/first`
+
+Expected client namespace for clients:
+
+- ClientNamespaceFirstClient: Client.ClientNamespace
+- ClientNamespaceSecondClient: Client.ClientNamespace.Second
+
+Expected client namespace for models:
+
+- FirstClientResult: Client.ClientNamespace.First
+- SecondClientResult: Client.ClientNamespace.Second
+- SecondClientEnumType: Client.ClientNamespace.Second.Sub
+
 ### Client_Naming_Header_request
 
 - Endpoint: `post /client/naming/header`
diff --git a/packages/azure-http-specs/specs/client/namespace/client.tsp b/packages/azure-http-specs/specs/client/namespace/client.tsp
new file mode 100644
index 0000000000..d3958b5522
--- /dev/null
+++ b/packages/azure-http-specs/specs/client/namespace/client.tsp
@@ -0,0 +1,36 @@
+import "./main.tsp";
+import "@azure-tools/typespec-client-generator-core";
+
+using TypeSpec.Http;
+using Spector;
+using Azure.ClientGenerator.Core;
+using Client.ClientNamespace;
+
+@route("/client/client-namespace")
+namespace ClientNameSpaceClient;
+
+@client({
+  name: "ClientNamespaceFirstClient",
+  service: Client.ClientNamespace,
+})
+@clientNamespace("client.clientnamespace", "java")
+@clientNamespace("client.clientnamespace", "python")
+interface ClientNamespaceFirstClient {
+  getFirst is First.getFirst;
+}
+@@clientNamespace(FirstModel, "client.clientnamespace.first", "java");
+@@clientNamespace(FirstModel, "client.clientnamespace.first", "python");
+
+@client({
+  name: "ClientNamespaceSecondClient",
+  service: Client.ClientNamespace,
+})
+@clientNamespace("client.clientnamespace.second", "java")
+@clientNamespace("client.clientnamespace.second", "python")
+namespace ClientNamespaceSecondClient {
+  op getSecond is Second.getSecond;
+}
+@@clientNamespace(Second.Model, "client.clientnamespace.second", "java");
+@@clientNamespace(Second.Model, "client.clientnamespace.second", "python");
+@@clientNamespace(Second.Model.SecondClientEnumType, "client.clientnamespace.second.sub", "java");
+@@clientNamespace(Second.Model.SecondClientEnumType, "client.clientnamespace.second.sub", "python");
diff --git a/packages/azure-http-specs/specs/client/namespace/main.tsp b/packages/azure-http-specs/specs/client/namespace/main.tsp
new file mode 100644
index 0000000000..fd8efdbd5d
--- /dev/null
+++ b/packages/azure-http-specs/specs/client/namespace/main.tsp
@@ -0,0 +1,51 @@
+import "@typespec/http";
+import "@typespec/spector";
+
+using TypeSpec.Http;
+using Spector;
+
+/** Illustrates the clientNamespace cases. */
+@scenarioService("/client/client-namespace")
+@scenario
+@scenarioDoc("""
+  Expected client namespace for clients:
+  - ClientNamespaceFirstClient: Client.ClientNamespace
+  - ClientNamespaceSecondClient: Client.ClientNamespace.Second
+  
+  Expected client namespace for models:
+  - FirstClientResult: Client.ClientNamespace.First
+  - SecondClientResult: Client.ClientNamespace.Second
+  - SecondClientEnumType: Client.ClientNamespace.Second.Sub
+  """)
+namespace Client.ClientNamespace;
+
+interface First {
+  #suppress "@azure-tools/cadl-ranch-expect/missing-scenario" "scenario defined in client.tsp"
+  @route("/first")
+  @get
+  getFirst(): FirstModel.FirstClientResult;
+}
+
+namespace FirstModel {
+  model FirstClientResult {
+    name: string;
+  }
+}
+
+namespace Second {
+  #suppress "@azure-tools/cadl-ranch-expect/missing-scenario" "scenario defined in client.tsp"
+  @route("/second")
+  @get
+  op getSecond(): Model.SecondClientResult;
+
+  namespace Model {
+    model SecondClientResult {
+      type: SecondClientEnumType;
+    }
+
+    union SecondClientEnumType {
+      string,
+      Second: "second",
+    }
+  }
+}
diff --git a/packages/azure-http-specs/specs/client/namespace/mockapi.ts b/packages/azure-http-specs/specs/client/namespace/mockapi.ts
new file mode 100644
index 0000000000..d588623451
--- /dev/null
+++ b/packages/azure-http-specs/specs/client/namespace/mockapi.ts
@@ -0,0 +1,30 @@
+import { json, passOnSuccess, ScenarioMockApi } from "@typespec/spec-api";
+
+export const Scenarios: Record<string, ScenarioMockApi> = {};
+
+Scenarios.Client_ClientNamespace = passOnSuccess([
+  {
+    uri: "/client/client-namespace/first",
+    method: "get",
+    request: {
+      body: {},
+    },
+    response: {
+      status: 200,
+      body: json({ name: "first" }),
+    },
+    kind: "MockApiDefinition",
+  },
+  {
+    uri: "/client/client-namespace/second",
+    method: "get",
+    request: {
+      body: {},
+    },
+    response: {
+      status: 200,
+      body: json({ type: "second" }),
+    },
+    kind: "MockApiDefinition",
+  },
+]);