diff --git a/src/Umbraco.Web.UI/appsettings.template.json b/src/Umbraco.Web.UI/appsettings.template.json
index 698eb83955..35a41bcedb 100644
--- a/src/Umbraco.Web.UI/appsettings.template.json
+++ b/src/Umbraco.Web.UI/appsettings.template.json
@@ -41,7 +41,7 @@
         "KeepUserLoggedIn": false,
         "UsernameIsEmail": true,
         "HideDisabledUsersInBackoffice": false,
-        "AllowedUserNameCharacters": "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-._@+\\",
+        "AllowedUserNameCharacters": "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-'._@+\\",
         "UserPassword": {
           "RequiredLength": 10,
           "RequireNonLetterOrDigit": false,