diff --git a/app/assets/javascripts/discourse/controllers/create-account.js.es6 b/app/assets/javascripts/discourse/controllers/create-account.js.es6
index 694c89d32..292f5624f 100644
--- a/app/assets/javascripts/discourse/controllers/create-account.js.es6
+++ b/app/assets/javascripts/discourse/controllers/create-account.js.es6
@@ -189,7 +189,7 @@ export default Discourse.Controller.extend(Discourse.ModalFunctionality, {
     }
 
     // If too short
-    if (this.get('accountUsername').length < 3) {
+    if (this.get('accountUsername').length < Discourse.SiteSettings.min_username_length) {
       return Discourse.InputValidation.create({
         failed: true,
         reason: I18n.t('user.username.too_short')
@@ -197,7 +197,7 @@ export default Discourse.Controller.extend(Discourse.ModalFunctionality, {
     }
 
     // If too long
-    if (this.get('accountUsername').length > 20) {
+    if (this.get('accountUsername').length > Discourse.SiteSettings.max_username_length) {
       return Discourse.InputValidation.create({
         failed: true,
         reason: I18n.t('user.username.too_long')
diff --git a/app/assets/javascripts/discourse/templates/modal/create_account.js.handlebars b/app/assets/javascripts/discourse/templates/modal/create_account.js.handlebars
index 541378270..17328de77 100644
--- a/app/assets/javascripts/discourse/templates/modal/create_account.js.handlebars
+++ b/app/assets/javascripts/discourse/templates/modal/create_account.js.handlebars
@@ -30,7 +30,7 @@
       <tr class="input">
             <td class="label"><label for='new-account-username'>{{i18n user.username.title}}</label></td>
             <td>
-            {{input value=accountUsername id="new-account-username" maxlength="20"}}
+            {{input value=accountUsername id="new-account-username" maxlength=Discourse.SiteSettings.max_username_length}}
             &nbsp;{{input-tip validation=usernameValidation}}
             </td>
       </tr>
diff --git a/test/javascripts/fixtures/site_settings_fixtures.js b/test/javascripts/fixtures/site_settings_fixtures.js
index 8fd7bb474..50a4ba613 100644
--- a/test/javascripts/fixtures/site_settings_fixtures.js
+++ b/test/javascripts/fixtures/site_settings_fixtures.js
@@ -1,3 +1,3 @@
 /*jshint maxlen:10000000 */
-Discourse.SiteSettingsOriginal = {"title":"Discourse Meta","logo_url":"/assets/logo.png","logo_small_url":"/assets/logo-single.png","traditional_markdown_linebreaks":false,"top_menu":"latest|new|unread|read|starred|categories","post_menu":"like|edit|flag|delete|share|bookmark|admin|reply","share_links":"twitter|facebook|google+|email","track_external_right_clicks":false,"must_approve_users":false,"ga_tracking_code":"UA-33736483-2","ga_domain_name":"","enable_long_polling":true,"polling_interval":3000,"anon_polling_interval":30000,"min_post_length":20,"max_post_length":16000,"min_topic_title_length":15,"max_topic_title_length":255,"min_private_message_title_length":2,"allow_uncategorized_topics":true,"min_search_term_length":3,"flush_timings_secs":5,"suppress_reply_directly_below":true,"email_domains_blacklist":"mailinator.com","email_domains_whitelist":null,"version_checks":true,"min_title_similar_length":10,"min_body_similar_length":15,"category_colors":"BF1E2E|F1592A|F7941D|9EB83B|3AB54A|12A89D|25AAE2|0E76BD|652D90|92278F|ED207B|8C6238|231F20|808281|B3B5B4|283890","max_upload_size_kb":1024,"category_featured_topics":6,"favicon_url":"/assets/favicon.ico","dynamic_favicon":false,"uncategorized_name":"uncategorized","uncategorized_color":"AB9364","uncategorized_text_color":"FFFFFF","invite_only":false,"login_required":false,"min_password_length":8,"enable_local_logins":true,"enable_google_logins":false,"enable_google_oauth2_logins":false,"enable_yahoo_logins":false,"enable_twitter_logins":false,"enable_facebook_logins":false,"enable_cas_logins":false,"enable_github_logins":false,"educate_until_posts":2,"topic_views_heat_low":1000,"topic_views_heat_medium":2000,"topic_views_heat_high":5000,"min_private_message_post_length":5,"faq_url":"","tos_url":"","privacy_policy_url":"","authorized_extensions":".jpg|.jpeg|.png|.gif|.txt","relative_date_duration":14,"delete_removed_posts_after":24,"delete_user_max_post_age":7, "default_code_lang": "lang-auto", "suppress_uncategorized_badge": true};
+Discourse.SiteSettingsOriginal = {"title":"Discourse Meta","logo_url":"/assets/logo.png","logo_small_url":"/assets/logo-single.png","traditional_markdown_linebreaks":false,"top_menu":"latest|new|unread|read|starred|categories","post_menu":"like|edit|flag|delete|share|bookmark|admin|reply","share_links":"twitter|facebook|google+|email","track_external_right_clicks":false,"must_approve_users":false,"ga_tracking_code":"UA-33736483-2","ga_domain_name":"","enable_long_polling":true,"polling_interval":3000,"anon_polling_interval":30000,"min_post_length":20,"max_post_length":16000,"min_topic_title_length":15,"max_topic_title_length":255,"min_private_message_title_length":2,"allow_uncategorized_topics":true,"min_search_term_length":3,"flush_timings_secs":5,"suppress_reply_directly_below":true,"email_domains_blacklist":"mailinator.com","email_domains_whitelist":null,"version_checks":true,"min_title_similar_length":10,"min_body_similar_length":15,"category_colors":"BF1E2E|F1592A|F7941D|9EB83B|3AB54A|12A89D|25AAE2|0E76BD|652D90|92278F|ED207B|8C6238|231F20|808281|B3B5B4|283890","max_upload_size_kb":1024,"category_featured_topics":6,"favicon_url":"/assets/favicon.ico","dynamic_favicon":false,"uncategorized_name":"uncategorized","uncategorized_color":"AB9364","uncategorized_text_color":"FFFFFF","invite_only":false,"login_required":false,"min_password_length":8,"enable_local_logins":true,"enable_google_logins":false,"enable_google_oauth2_logins":false,"enable_yahoo_logins":false,"enable_twitter_logins":false,"enable_facebook_logins":false,"enable_cas_logins":false,"enable_github_logins":false,"educate_until_posts":2,"topic_views_heat_low":1000,"topic_views_heat_medium":2000,"topic_views_heat_high":5000,"min_private_message_post_length":5,"faq_url":"","tos_url":"","privacy_policy_url":"","authorized_extensions":".jpg|.jpeg|.png|.gif|.txt","relative_date_duration":14,"delete_removed_posts_after":24,"delete_user_max_post_age":7, "default_code_lang": "lang-auto", "suppress_uncategorized_badge": true, "min_username_length": 3, "max_username_length": 20};
 Discourse.SiteSettings = jQuery.extend(true, {}, Discourse.SiteSettingsOriginal);