diff --git a/aider/coder.py b/aider/coder.py
index 9fc78c3be..99ae29e28 100755
--- a/aider/coder.py
+++ b/aider/coder.py
@@ -50,11 +50,12 @@ class Coder:
         map_tokens=1024,
         verbose=False,
         openai_api_key=None,
+        openai_api_base=None,
     ):
-        if openai_api_key:
-            openai.api_key = openai_api_key
-        else:
+        if not openai_api_key:
             raise MissingAPIKeyError("No OpenAI API key provided.")
+        openai.api_key = openai_api_key
+        openai.api_base = openai_api_base
 
         self.verbose = verbose
         self.abs_fnames = set()
diff --git a/aider/main.py b/aider/main.py
index 3bba81d57..8cc34ac12 100644
--- a/aider/main.py
+++ b/aider/main.py
@@ -151,6 +151,12 @@ def main(args=None, input=None, output=None):
         help="Specify the OpenAI API key",
         env_var="OPENAI_API_KEY",
     )
+    parser.add_argument(
+        "--openai-api-base",
+        metavar="OPENAI_API_BASE",
+        default="https://api.openai.com/v1",
+        help="Specify the OpenAI API base endpoint (default: https://api.openai.com/v1)",
+    )
     parser.add_argument(
         "--dry-run",
         action="store_true",
@@ -221,6 +227,7 @@ def main(args=None, input=None, output=None):
         map_tokens=args.map_tokens,
         verbose=args.verbose,
         openai_api_key=args.openai_api_key,
+        openai_api_base=args.openai_api_base,
     )
 
     if args.dirty_commits: