diff --git a/docs/reference/commandline/cli.md b/docs/reference/commandline/cli.md
index 4d1a0c7961..6a9a1d85fb 100644
--- a/docs/reference/commandline/cli.md
+++ b/docs/reference/commandline/cli.md
@@ -38,6 +38,7 @@ the [installation](../../installation/index.md) instructions for your operating
 For easy reference, the following list of environment variables are supported
 by the `docker` command line:
 
+* `DOCKER_API_VERSION` The API version to use (e.g. `1.19`)
 * `DOCKER_CONFIG` The location of your client configuration files.
 * `DOCKER_CERT_PATH` The location of your authentication keys.
 * `DOCKER_DRIVER` The graph driver to use.