diff --git a/app/models/mailer.rb b/app/models/mailer.rb
index ddbc7b394..7721997f6 100644
--- a/app/models/mailer.rb
+++ b/app/models/mailer.rb
@@ -661,16 +661,25 @@ class Mailer < ActionMailer::Base
   end
 
   def mail(headers={}, &block)
-    # Add a display name to the From field if Setting.mail_from does not
-    # include it
     begin
+      # Add a display name to the From field if Setting.mail_from does not
+      # include it
       mail_from = Mail::Address.new(Setting.mail_from)
       if mail_from.display_name.blank? && mail_from.comments.blank?
         mail_from.display_name =
           @author&.logged? ? @author.name : Setting.app_title
       end
       from = mail_from.format
-      list_id = "<#{mail_from.address.to_s.tr('@', '.')}>"
+
+      # Construct the value of the List-Id header field
+      from_addr = mail_from.address.to_s
+      project_identifier = self.headers['X-Redmine-Project']&.value
+      list_id = if project_identifier.present?
+                  "<#{project_identifier}.#{from_addr.tr('@', '.')}>"
+                else
+                  # Emails outside of a project context
+                  "<#{from_addr.tr('@', '.')}>"
+                end
     rescue Mail::Field::IncompleteParseError
       # Use Setting.mail_from as it is if Mail::Address cannot parse it
       # (probably the emission address is not RFC compliant)
diff --git a/test/unit/mailer_test.rb b/test/unit/mailer_test.rb
index 0506e27d2..afead7a47 100644
--- a/test/unit/mailer_test.rb
+++ b/test/unit/mailer_test.rb
@@ -220,7 +220,7 @@ class MailerTest < ActiveSupport::TestCase
     assert_equal 'All', mail.header['X-Auto-Response-Suppress'].to_s
     assert_equal 'auto-generated', mail.header['Auto-Submitted'].to_s
     # List-Id should not include the display name "Redmine"
-    assert_equal '<redmine.example.net>', mail.header['List-Id'].to_s
+    assert_equal '<ecookbook.redmine.example.net>', mail.header['List-Id'].to_s
     assert_equal 'Bug', mail.header['X-Redmine-Issue-Tracker'].to_s
     assert_equal 'Low', mail.header['X-Redmine-Issue-Priority'].to_s
   end
@@ -327,6 +327,23 @@ class MailerTest < ActiveSupport::TestCase
     end
   end
 
+  def test_list_id_header_should_include_project_identifier
+    with_settings :mail_from => 'redmine@example.net' do
+      content = WikiContent.find(1)
+      Mailer.deliver_wiki_content_added(content)
+      mail = last_email
+      assert_equal '<ecookbook.redmine.example.net>', mail.header['List-Id'].to_s
+    end
+  end
+
+  def test_list_id_header_excludes_project_identifier_for_non_project_emails
+    with_settings :mail_from => 'redmine@example.net' do
+      Mailer.deliver_test_email(User.find(1))
+      mail = last_email
+      assert_equal '<redmine.example.net>', mail.header['List-Id'].to_s
+    end
+  end
+
   def test_should_not_send_email_without_recipient
     news = News.first
     user = news.author