diff --git a/src/google/adk/cli/adk_web_server.py b/src/google/adk/cli/adk_web_server.py
index b073f1a7b0..42ae092f42 100644
--- a/src/google/adk/cli/adk_web_server.py
+++ b/src/google/adk/cli/adk_web_server.py
@@ -436,6 +436,7 @@ def __init__(
       extra_plugins: Optional[list[str]] = None,
       logo_text: Optional[str] = None,
       logo_image_url: Optional[str] = None,
+      root_path: Optional[str] = None,
   ):
     self.agent_loader = agent_loader
     self.session_service = session_service
@@ -452,6 +453,7 @@ def __init__(
     self.runners_to_clean: set[str] = set()
     self.current_app_name_ref: SharedValue[str] = SharedValue(value="")
     self.runner_dict = {}
+    self.root_path = root_path
 
   async def get_runner_async(self, app_name: str) -> Runner:
     """Returns the cached runner for the given app."""
@@ -559,6 +561,7 @@ def _setup_runtime_config(self, web_assets_dir: str):
           " overwritten.",
           runtime_config_path,
       )
+    runtime_config["backendUrl"] = self.root_path if self.root_path else ""
 
     # Set custom logo config.
     if self.logo_text or self.logo_image_url:
@@ -1562,6 +1565,9 @@ async def process_messages():
       mimetypes.add_type("application/javascript", ".js", True)
       mimetypes.add_type("text/javascript", ".js", True)
 
+      devRedirectUrl = "/dev-ui/"
+      if self.root_path:
+        devRedirectUrl = self.root_path + "/dev-ui/"
       @app.get("/dev-ui/config")
       async def get_ui_config():
         return {
@@ -1571,11 +1577,11 @@ async def get_ui_config():
 
       @app.get("/")
       async def redirect_root_to_dev_ui():
-        return RedirectResponse("/dev-ui/")
+        return RedirectResponse(devRedirectUrl)
 
       @app.get("/dev-ui")
       async def redirect_dev_ui_add_slash():
-        return RedirectResponse("/dev-ui/")
+        return RedirectResponse(devRedirectUrl)
 
       app.mount(
           "/dev-ui/",
diff --git a/src/google/adk/cli/cli_tools_click.py b/src/google/adk/cli/cli_tools_click.py
index b841e017ad..dbd81dbdb2 100644
--- a/src/google/adk/cli/cli_tools_click.py
+++ b/src/google/adk/cli/cli_tools_click.py
@@ -1028,6 +1028,11 @@ def decorator(func):
         ),
         multiple=True,
     )
+    @click.option(
+        "--root_path",
+        type=str,
+        default = None,
+    )
     @functools.wraps(func)
     @click.pass_context
     def wrapper(ctx, *args, **kwargs):
@@ -1065,6 +1070,7 @@ def cli_web(
     allow_origins: Optional[list[str]] = None,
     host: str = "127.0.0.1",
     port: int = 8000,
+    root_path: str = None,
     trace_to_cloud: bool = False,
     otel_to_cloud: bool = False,
     reload: bool = True,
@@ -1128,6 +1134,7 @@ async def _lifespan(app: FastAPI):
       a2a=a2a,
       host=host,
       port=port,
+      root_path=root_path,
       reload_agents=reload_agents,
       extra_plugins=extra_plugins,
       logo_text=logo_text,
diff --git a/src/google/adk/cli/fast_api.py b/src/google/adk/cli/fast_api.py
index 7e1e18bec9..d284fa88c7 100644
--- a/src/google/adk/cli/fast_api.py
+++ b/src/google/adk/cli/fast_api.py
@@ -64,6 +64,7 @@ def get_fast_api_app(
     a2a: bool = False,
     host: str = "127.0.0.1",
     port: int = 8000,
+    root_path = None,
     trace_to_cloud: bool = False,
     otel_to_cloud: bool = False,
     reload_agents: bool = False,
@@ -144,6 +145,7 @@ def get_fast_api_app(
       extra_plugins=extra_plugins,
       logo_text=logo_text,
       logo_image_url=logo_image_url,
+      root_path=root_path
   )
 
   # Callbacks & other optional args for when constructing the FastAPI instance