diff --git a/aider/coder.py b/aider/coder.py
index f23fd6dfc..1890d2d4a 100755
--- a/aider/coder.py
+++ b/aider/coder.py
@@ -20,9 +20,6 @@ from aider import prompts
 from aider.commands import Commands
 from aider.repomap import RepoMap
 
-openai.api_key = os.getenv("OPENAI_API_KEY")
-
-
 class Coder:
     abs_fnames = None
     repo = None
@@ -41,7 +38,12 @@ class Coder:
         dry_run=False,
         use_ctags=False,
         verbose=False,
+        openai_api_key=None,
     ):
+        if openai_api_key:
+            openai.api_key = openai_api_key
+        else:
+            openai.api_key = os.getenv("OPENAI_API_KEY")
         self.verbose = verbose
         self.abs_fnames = set()
         self.cur_messages = []
diff --git a/aider/main.py b/aider/main.py
index 20a461fa4..ba91e86eb 100644
--- a/aider/main.py
+++ b/aider/main.py
@@ -127,6 +127,11 @@ def main(args=None, input=None, output=None):
         dest="dirty_commits",
         help="Disable dirty commit of changes",
     )
+    parser.add_argument(
+        "--openai-api-key",
+        metavar="OPENAI_API_KEY",
+        help="Specify the OpenAI API key",
+    )
     parser.add_argument(
         "--dry-run",
         action="store_true",
@@ -194,6 +199,7 @@ def main(args=None, input=None, output=None):
         dry_run=args.dry_run,
         use_ctags=args.ctags,
         verbose=args.verbose,
+        openai_api_key=args.openai_api_key,
     )
     if args.dirty_commits:
         coder.commit(ask=True, prefix="wip: ", which="repo_files")