diff --git a/invokeai/app/api_app.py b/invokeai/app/api_app.py
index ce61964246..bab5121b28 100644
--- a/invokeai/app/api_app.py
+++ b/invokeai/app/api_app.py
@@ -7,13 +7,14 @@
 
 import torch
 import uvicorn
-from fastapi import FastAPI
+from fastapi import FastAPI, Request
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.middleware.gzip import GZipMiddleware
 from fastapi.openapi.docs import get_redoc_html, get_swagger_ui_html
-from fastapi.responses import HTMLResponse
+from fastapi.responses import HTMLResponse, RedirectResponse
 from fastapi_events.handlers.local import local_handler
 from fastapi_events.middleware import EventHandlerASGIMiddleware
+from starlette.middleware.base import BaseHTTPMiddleware, RequestResponseEndpoint
 from torch.backends.mps import is_available as is_mps_available
 
 # for PyCharm:
@@ -78,6 +79,29 @@ async def lifespan(app: FastAPI):
     lifespan=lifespan,
 )
 
+
+class RedirectRootWithQueryStringMiddleware(BaseHTTPMiddleware):
+    """When a request is made to the root path with a query string, redirect to the root path without the query string.
+
+    For example, to force a Gradio app to use dark mode, users may append `?__theme=dark` to the URL. Their browser may
+    have this query string saved in history or a bookmark, so when the user navigates to `http://127.0.0.1:9090/`, the
+    browser takes them to `http://127.0.0.1:9090/?__theme=dark`.
+
+    This breaks the static file serving in the UI, so we redirect the user to the root path without the query string.
+    """
+
+    async def dispatch(self, request: Request, call_next: RequestResponseEndpoint):
+        if request.url.path == "/" and request.url.query:
+            return RedirectResponse(url="/")
+
+        response = await call_next(request)
+        return response
+
+
+# Add the middleware
+app.add_middleware(RedirectRootWithQueryStringMiddleware)
+
+
 # Add event handler
 event_handler_id: int = id(app)
 app.add_middleware(