diff --git a/backend/open_webui/env.py b/backend/open_webui/env.py
index 26a8d376c5..e734a2f865 100644
--- a/backend/open_webui/env.py
+++ b/backend/open_webui/env.py
@@ -525,6 +525,12 @@ WEBUI_AUTH_TRUSTED_NAME_HEADER = os.environ.get('WEBUI_AUTH_TRUSTED_NAME_HEADER'
 WEBUI_AUTH_TRUSTED_GROUPS_HEADER = os.environ.get('WEBUI_AUTH_TRUSTED_GROUPS_HEADER', None)
 WEBUI_AUTH_TRUSTED_ROLE_HEADER = os.environ.get('WEBUI_AUTH_TRUSTED_ROLE_HEADER', None)
 
+# Custom header name for API key authentication.  Defaults to 'x-api-key'.
+# Useful when Open WebUI sits behind a reverse proxy / API gateway that
+# already uses the Authorization header for its own authentication — set
+# this to a unique header (e.g. 'X-OpenWebUI-Key') so the middleware
+# checks the custom header instead and avoids the 401 short-circuit.
+CUSTOM_API_KEY_HEADER = os.environ.get('CUSTOM_API_KEY_HEADER', 'x-api-key')
 
 ENABLE_PASSWORD_VALIDATION = os.environ.get('ENABLE_PASSWORD_VALIDATION', 'False').lower() == 'true'
 PASSWORD_VALIDATION_REGEX_PATTERN = os.environ.get(
diff --git a/backend/open_webui/utils/asgi_middleware.py b/backend/open_webui/utils/asgi_middleware.py
index 05389d8f94..e3872dd231 100644
--- a/backend/open_webui/utils/asgi_middleware.py
+++ b/backend/open_webui/utils/asgi_middleware.py
@@ -41,6 +41,7 @@ from starlette.datastructures import MutableHeaders
 from starlette.requests import Request
 from starlette.types import ASGIApp, Message, Receive, Scope, Send
 
+from open_webui.env import CUSTOM_API_KEY_HEADER
 from open_webui.internal.db import ScopedSession
 from open_webui.utils.auth import get_http_authorization_cred
 
@@ -119,9 +120,16 @@ class CommitSessionMiddleware:
 
 
 class AuthTokenMiddleware:
-    """Extract the bearer/cookie/x-api-key credential and stash it on
+    """Extract the bearer/cookie/API-key credential and stash it on
     `request.state.token`.
 
+    The header used for API-key transport is controlled by the
+    ``CUSTOM_API_KEY_HEADER`` environment variable (default ``x-api-key``).
+    This is useful when Open WebUI sits behind a reverse proxy that
+    consumes the ``Authorization`` header for its own authentication —
+    set the env var to a unique header (e.g. ``X-OpenWebUI-Key``) so
+    the middleware checks that instead and avoids the 401 short-circuit.
+
     Routes that depend on `get_verified_user` etc. read this state.
     Also exposes `request.state.enable_api_keys` (snapshotted at request
     entry from runtime config) and stamps an `X-Process-Time` response
@@ -146,7 +154,7 @@ class AuthTokenMiddleware:
             if cookie_token:
                 token = HTTPAuthorizationCredentials(scheme='Bearer', credentials=cookie_token)
         if token is None:
-            api_key = request.headers.get('x-api-key')
+            api_key = request.headers.get(CUSTOM_API_KEY_HEADER)
             if api_key:
                 token = HTTPAuthorizationCredentials(scheme='Bearer', credentials=api_key)