diff --git a/README.md b/README.md
index b87a8a37..ba954771 100644
--- a/README.md
+++ b/README.md
@@ -267,6 +267,7 @@ docker run -name gitlab -d -h git.local.host \
 Below is the complete list of available options that can be used to customize your gitlab installation.
 
 - **GITLAB_HOST**: The hostname of the GitLab server. Defaults to localhost
+- **GITLAB_POST**: The port of the GitLab server. Defaults to 80
 - **GITLAB_EMAIL**: The email address for the GitLab server. Defaults to gitlab@localhost.
 - **GITLAB_SUPPORT**: The support email address for the GitLab server. Defaults to support@localhost.
 - **GITLAB_SIGNUP**: Enable or disable user signups. Default is false.