diff --git a/django/contrib/admin/static/admin/js/collapse.js b/django/contrib/admin/static/admin/js/collapse.js
deleted file mode 100644
index c6c7b0f68a2..00000000000
--- a/django/contrib/admin/static/admin/js/collapse.js
+++ /dev/null
@@ -1,43 +0,0 @@
-/*global gettext*/
-'use strict';
-{
-    window.addEventListener('load', function() {
-        // Add anchor tag for Show/Hide link
-        const fieldsets = document.querySelectorAll('fieldset.collapse');
-        for (const [i, elem] of fieldsets.entries()) {
-            // Don't hide if fields in this fieldset have errors
-            if (elem.querySelectorAll('div.errors, ul.errorlist').length === 0) {
-                elem.classList.add('collapsed');
-                const h2 = elem.querySelector('h2');
-                const link = document.createElement('a');
-                link.id = 'fieldsetcollapser' + i;
-                link.className = 'collapse-toggle';
-                link.href = '#';
-                link.textContent = gettext('Show');
-                h2.appendChild(document.createTextNode(' ('));
-                h2.appendChild(link);
-                h2.appendChild(document.createTextNode(')'));
-            }
-        }
-        // Add toggle to hide/show anchor tag
-        const toggleFunc = function(ev) {
-            if (ev.target.matches('.collapse-toggle')) {
-                ev.preventDefault();
-                ev.stopPropagation();
-                const fieldset = ev.target.closest('fieldset');
-                if (fieldset.classList.contains('collapsed')) {
-                    // Show
-                    ev.target.textContent = gettext('Hide');
-                    fieldset.classList.remove('collapsed');
-                } else {
-                    // Hide
-                    ev.target.textContent = gettext('Show');
-                    fieldset.classList.add('collapsed');
-                }
-            }
-        };
-        document.querySelectorAll('fieldset.module').forEach(function(el) {
-            el.addEventListener('click', toggleFunc);
-        });
-    });
-}
diff --git a/docs/releases/5.1.txt b/docs/releases/5.1.txt
index e4f0b374025..faaa5c98338 100644
--- a/docs/releases/5.1.txt
+++ b/docs/releases/5.1.txt
@@ -425,6 +425,9 @@ Miscellaneous
   when the fieldset has a name and use the ``collapse`` class, now includes
   ``<details>`` and ``<summary>`` elements.
 
+* The JavaScript file ``collapse.js`` is removed since it is no longer needed
+  in the Django admin site.
+
 * :meth:`.SimpleTestCase.assertURLEqual` and
   :meth:`~django.test.SimpleTestCase.assertInHTML` now add ``": "`` to the
   ``msg_prefix``. This is consistent with the behavior of other assertions.
diff --git a/js_tests/tests.html b/js_tests/tests.html
index adeac661253..011998e5a75 100644
--- a/js_tests/tests.html
+++ b/js_tests/tests.html
@@ -143,7 +143,6 @@
     <script src='./admin/inlines.test.js'></script>
 
     <script src='../django/contrib/admin/static/admin/js/actions.js' data-cover></script>
-    <script src='../django/contrib/admin/static/admin/js/collapse.js' data-cover></script>
     <script src='../django/contrib/admin/static/admin/js/prepopulate.js' data-cover></script>
     <script src='../django/contrib/admin/static/admin/js/urlify.js' data-cover></script>
     <script src='./admin/URLify.test.js'></script>