diff --git a/app/models/account.rb b/app/models/account.rb
index 44963f3e636905..acba6770b29593 100644
--- a/app/models/account.rb
+++ b/app/models/account.rb
@@ -49,7 +49,7 @@
 #
 
 class Account < ApplicationRecord
-  USERNAME_RE = /[a-z0-9_]+([a-z0-9_\.]+[a-z0-9_]+)?/i
+  USERNAME_RE = /[a-z0-9_]+([a-z0-9_\.-]+[a-z0-9_]+)?/i
   MENTION_RE  = /(?<=^|[^\/[:word:]])@((#{USERNAME_RE})(?:@[a-z0-9\.\-]+[a-z0-9]+)?)/i
 
   include AccountAvatar
diff --git a/spec/models/account_spec.rb b/spec/models/account_spec.rb
index 60d13d32e90446..b25b66d2dc6384 100644
--- a/spec/models/account_spec.rb
+++ b/spec/models/account_spec.rb
@@ -618,9 +618,15 @@
         expect(account).not_to model_have_error_on_field(:username)
       end
 
-      it 'is invalid if the username doesn\'t only contains letters, numbers and underscores' do
+      it 'is valid even if the username contains hyphens' do
         account = Fabricate.build(:account, domain: 'domain', username: 'the-doctor')
         account.valid?
+        expect(account).to_not model_have_error_on_field(:username)
+      end
+
+      it 'is invalid if the username doesn\'t only contains letters, numbers, underscores and hyphens' do
+        account = Fabricate.build(:account, domain: 'domain', username: 'the doctor')
+        account.valid?
         expect(account).to model_have_error_on_field(:username)
       end