diff --git a/config/environments/development.rb b/config/environments/development.rb
index ee06ba01b4..7079245f7d 100644
--- a/config/environments/development.rb
+++ b/config/environments/development.rb
@@ -49,6 +49,6 @@ Discourse::Application.configure do
   require 'rbtrace'
 
   if emails = GlobalSetting.developer_emails
-    config.developer_emails = emails.split(",").map(&:strip)
+    config.developer_emails = emails.split(",").map(&:downcase).map(&:strip)
   end
 end
diff --git a/config/environments/production.rb b/config/environments/production.rb
index 35c21bf226..f73b6e2dc9 100644
--- a/config/environments/production.rb
+++ b/config/environments/production.rb
@@ -60,7 +60,7 @@ Discourse::Application.configure do
   # developers have god like rights and may impersonate anyone in the system
   # normal admins may only impersonate other moderators (not admins)
   if emails = GlobalSetting.developer_emails
-    config.developer_emails = emails.split(",").map(&:strip)
+    config.developer_emails = emails.split(",").map(&:downcase).map(&:strip)
   end
 
 end