diff --git a/app/models/account.rb b/app/models/account.rb
index 46d32a36ef418dc9dad8fa906c11e179d7af2b54..f25263306439db9f297c0105d77afc798dfa465b 100644
--- a/app/models/account.rb
+++ b/app/models/account.rb
@@ -46,7 +46,7 @@
 #
 
 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 9133616a2a9c9d993ff3f3bbdf8cf3c4b5270ab1..f7f78d34c616099bef1ec1743b7b2562667776ef 100644
--- a/spec/models/account_spec.rb
+++ b/spec/models/account_spec.rb
@@ -618,9 +618,15 @@ RSpec.describe Account, type: :model do
         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