diff --git a/lib/validators/email_validator.rb b/lib/validators/email_validator.rb
index e0e759571..c9f588976 100644
--- a/lib/validators/email_validator.rb
+++ b/lib/validators/email_validator.rb
@@ -17,7 +17,7 @@ class EmailValidator < ActiveModel::EachValidator
 
   def email_in_restriction_setting?(setting, value)
     domains = setting.gsub('.', '\.')
-    regexp = Regexp.new("@(#{domains})", true)
+    regexp = Regexp.new("@(.+\.)?(#{domains})", true)
     value =~ regexp
   end
 
diff --git a/spec/models/user_spec.rb b/spec/models/user_spec.rb
index 58a48f71d..799b1e9b9 100644
--- a/spec/models/user_spec.rb
+++ b/spec/models/user_spec.rb
@@ -440,6 +440,11 @@ describe User do
       expect(Fabricate.build(:user, email: 'notgood@TRASHMAIL.NET')).not_to be_valid
     end
 
+    it 'should reject emails based on the email_domains_blacklist site setting matching subdomain' do
+      SiteSetting.stubs(:email_domains_blacklist).returns('domain.com')
+      expect(Fabricate.build(:user, email: 'notgood@sub.domain.com')).not_to be_valid
+    end
+
     it 'blacklist should not reject developer emails' do
       Rails.configuration.stubs(:developer_emails).returns('developer@discourse.org')
       SiteSetting.stubs(:email_domains_blacklist).returns('discourse.org')