diff --git a/app/models/user.rb b/app/models/user.rb
index 8e0dc91b2a7..48629c58490 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -244,7 +244,7 @@ class User < ActiveRecord::Base
   scope :blocked, -> { with_states(:blocked, :ldap_blocked) }
   scope :external, -> { where(external: true) }
   scope :active, -> { with_state(:active).non_internal }
-  scope :without_projects, -> { where('id NOT IN (SELECT DISTINCT(user_id) FROM members WHERE user_id IS NOT NULL AND requested_at IS NULL)') }
+  scope :without_projects, -> { joins('LEFT JOIN project_authorizations ON users.id = project_authorizations.user_id').where(project_authorizations: { user_id: nil }) }
   scope :todo_authors, ->(user_id, state) { where(id: Todo.where(user_id: user_id, state: state).select(:author_id)) }
   scope :order_recent_sign_in, -> { reorder(Gitlab::Database.nulls_last_order('current_sign_in_at', 'DESC')) }
   scope :order_oldest_sign_in, -> { reorder(Gitlab::Database.nulls_last_order('current_sign_in_at', 'ASC')) }
diff --git a/changelogs/unreleased/dm-user-without-projects-performance.yml b/changelogs/unreleased/dm-user-without-projects-performance.yml
new file mode 100644
index 00000000000..e7fc0ae6d54
--- /dev/null
+++ b/changelogs/unreleased/dm-user-without-projects-performance.yml
@@ -0,0 +1,5 @@
+---
+title: Improve performance of listing users without projects
+merge_request:
+author:
+type: performance