diff --git a/doc/advanced/config-cheat-sheet.en-us.md b/doc/advanced/config-cheat-sheet.en-us.md
index b0ab78d2..a3bded67 100644
--- a/doc/advanced/config-cheat-sheet.en-us.md
+++ b/doc/advanced/config-cheat-sheet.en-us.md
@@ -194,6 +194,8 @@ Values containing `#` or `;` must be quoted using `` ` `` or `"""`.
 - `RECAPTCHA_SITEKEY`: **""**: Go to https://www.google.com/recaptcha/admin to get a sitekey for recaptcha.
 - `DEFAULT_ENABLE_DEPENDENCIES`: **true** Enable this to have dependencies enabled by default.
 - `ENABLE_USER_HEATMAP`: **true** Enable this to display the heatmap on users profiles.
+- `EMAIL_DOMAIN_WHITELIST`: **\<empty\>**: If non-empty, list of domain names that can only be used to register
+  on this instance.
 
 ## Webhook (`webhook`)