diff --git a/gptel-curl.el b/gptel-curl.el
index 7953790..4f2348f 100644
--- a/gptel-curl.el
+++ b/gptel-curl.el
@@ -50,7 +50,8 @@ PROMPTS is the data to send, TOKEN is a unique identifier."
          (api-key
           (cond
            ((stringp gptel-api-key) gptel-api-key)
-           ((functionp gptel-api-key) (funcall gptel-api-key))))
+           ((functionp gptel-api-key) (funcall gptel-api-key))
+           (t (setq gptel-api-key (read-passwd "OpenAI API key: ")))))
          (headers
           `(("Content-Type" . "application/json")
             ("Authorization" . ,(concat "Bearer " api-key)))))
diff --git a/gptel.el b/gptel.el
index f93f44c..b90bf54 100644
--- a/gptel.el
+++ b/gptel.el
@@ -278,7 +278,8 @@ Return the message received."
          (api-key
           (cond
            ((stringp gptel-api-key) gptel-api-key)
-           ((functionp gptel-api-key) (funcall gptel-api-key))))
+           ((functionp gptel-api-key) (funcall gptel-api-key))
+           (t (setq gptel-api-key (read-passwd "OpenAI API key: ")))))
          (url-request-method "POST")
          (url-request-extra-headers
          `(("Content-Type" . "application/json")