diff --git a/app/views/shared/milestones/_issuables.html.haml b/app/views/shared/milestones/_issuables.html.haml
index 15ff5b8a27e950217fc4b28c30657353a9b6034e..c8fd45c431998558683b744d2d18b27deee3ad74 100644
--- a/app/views/shared/milestones/_issuables.html.haml
+++ b/app/views/shared/milestones/_issuables.html.haml
@@ -9,6 +9,7 @@
     - if show_counter
       .right
         = issuables.size
+      .pull-right= number_with_delimiter(issuables.size)
 
   - class_prefix = dom_class(issuables).pluralize
   %ul{ class: "well-list #{class_prefix}-sortable-list", id: "#{class_prefix}-list-#{id}", "data-state" => id }
diff --git a/changelogs/unreleased/25277-milestone-counter-number-with-delimiter.yml b/changelogs/unreleased/25277-milestone-counter-number-with-delimiter.yml
new file mode 100644
index 0000000000000000000000000000000000000000..0c9853de3b6ee09ec061e126007bdb91c7f04d77
--- /dev/null
+++ b/changelogs/unreleased/25277-milestone-counter-number-with-delimiter.yml
@@ -0,0 +1,4 @@
+---
+title: Added number_with_delimiter to counter on milestone panels
+merge_request: 
+author: Ryan Harris
diff --git a/spec/javascripts/fixtures/issuables.html.haml b/spec/javascripts/fixtures/issuables.html.haml
new file mode 100644
index 0000000000000000000000000000000000000000..42daf8508d9cbb4efed4fd5f1b7d53b6a9ac5cd5
--- /dev/null
+++ b/spec/javascripts/fixtures/issuables.html.haml
@@ -0,0 +1,5 @@
+.panel.panel-default
+  .panel-heading
+    Unstarted Issues (open and unassigned)
+    .pull-right
+    1
diff --git a/spec/javascripts/milestones_spec.js.es6 b/spec/javascripts/milestones_spec.js.es6
new file mode 100644
index 0000000000000000000000000000000000000000..7c1f9cbde124ea4eb8213b22912df946f729d847
--- /dev/null
+++ b/spec/javascripts/milestones_spec.js.es6
@@ -0,0 +1,21 @@
+/*= require jquery */
+(() => {
+  describe('MilestonePanel', () => {
+    const issuesCount = '.pull-right';
+    const fixtureTemplate = 'issuables.html';
+
+    function setIssuesCount(newCount) {
+      $(issuesCount).text(newCount);
+    }
+
+    fixture.preload(fixtureTemplate);
+    beforeEach(() => {
+      fixture.load(fixtureTemplate);
+    });
+
+    it('should add delimiter to the issues count', () => {
+      setIssuesCount(1000);
+      expect($(issuesCount).text()).toEqual('1,000');
+    });
+  });
+})();