diff --git a/lang/en/access.php b/lang/en/access.php
index 6fe361641fe..ae8e241fb74 100644
--- a/lang/en/access.php
+++ b/lang/en/access.php
@@ -29,6 +29,8 @@ $string['accessstatement'] = 'Accessibility statement';
 $string['activitynext'] = 'Next activity';
 $string['activityprev'] = 'Previous activity';
 $string['breadcrumb'] = 'Navigation bar';
+$string['eventcontextlocked'] = 'Context frozen';
+$string['eventcontextunlocked'] = 'Context unfrozen';
 $string['hideblocka'] = 'Hide {$a} block';
 $string['showblocka'] = 'Show {$a} block';
 $string['sitemap'] = 'Site map';
diff --git a/lib/accesslib.php b/lib/accesslib.php
index e80ba19c445..b3f9a41356c 100644
--- a/lib/accesslib.php
+++ b/lib/accesslib.php
@@ -5254,6 +5254,15 @@ abstract class context extends stdClass implements IteratorAggregate {
         $this->_locked = $locked;
         $DB->set_field('context', 'locked', (int) $locked, ['id' => $this->id]);
         $this->mark_dirty();
+
+        if ($locked) {
+            $eventname = '\\core\\event\\context_locked';
+        } else {
+            $eventname = '\\core\\event\\context_unlocked';
+        }
+        $event = $eventname::create(['context' => $this, 'objectid' => $this->id]);
+        $event->trigger();
+
         self::reset_caches();
 
         return $this;
diff --git a/lib/classes/event/context_locked.php b/lib/classes/event/context_locked.php
new file mode 100644
index 00000000000..f4bf9904c0b
--- /dev/null
+++ b/lib/classes/event/context_locked.php
@@ -0,0 +1,85 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Context locked event.
+ *
+ * @package    core_access
+ * @copyright  2019 University of Nottingham
+ * @author     Neill Magill <neill.magill@nottingham.ac.uk>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core\event;
+
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * Event triggered after a context has been frozen.
+ *
+ * @package    core_access
+ * @since      Moodle 3.8
+ * @copyright  2019 University of Nottingham
+ * @author     Neill Magill <neill.magill@nottingham.ac.uk>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class context_locked extends base {
+    /**
+     * Returns description of what happened.
+     *
+     * @return string
+     */
+    public function get_description() {
+        return "The user with id '$this->userid' locked the context with id '$this->objectid' ";
+    }
+
+    /**
+     * Return localised event name.
+     *
+     * @return string
+     */
+    public static function get_name() {
+        return get_string('eventcontextlocked', 'access');
+    }
+
+    /**
+     * Get URL related to the action
+     *
+     * @return \moodle_url
+     */
+    public function get_url() {
+        // Try to get the url for the context.
+        try {
+            $context = \context::instance_by_id($this->objectid);
+            $url = $context->get_url();
+        } catch (\dml_missing_record_exception $e) {
+            // The context no longer exists, give them the system url instead.
+            $url = \context_system::instance()->get_url();
+        }
+        return $url;
+    }
+
+    /**
+     * Init method.
+     *
+     * @return void
+     */
+    protected function init() {
+        $this->data['crud'] = 'u';
+        $this->data['edulevel'] = self::LEVEL_OTHER;
+        $this->data['objecttable'] = 'context';
+    }
+}
diff --git a/lib/classes/event/context_unlocked.php b/lib/classes/event/context_unlocked.php
new file mode 100644
index 00000000000..92e6ece1c5c
--- /dev/null
+++ b/lib/classes/event/context_unlocked.php
@@ -0,0 +1,85 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Context unlocked event.
+ *
+ * @package    core_access
+ * @copyright  2019 University of Nottingham
+ * @author     Neill Magill <neill.magill@nottingham.ac.uk>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core\event;
+
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * Event triggered after a context has been unfrozen.
+ *
+ * @package    core_access
+ * @since      Moodle 3.8
+ * @copyright  2019 University of Nottingham
+ * @author     Neill Magill <neill.magill@nottingham.ac.uk>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class context_unlocked extends base {
+    /**
+     * Returns description of what happened.
+     *
+     * @return string
+     */
+    public function get_description() {
+        return "The user with id '$this->userid' unlocked the context with id '$this->objectid' ";
+    }
+
+    /**
+     * Return localised event name.
+     *
+     * @return string
+     */
+    public static function get_name() {
+        return get_string('eventcontextunlocked', 'access');
+    }
+
+    /**
+     * Get URL related to the action
+     *
+     * @return \moodle_url
+     */
+    public function get_url() {
+        // Try to get the url for the context.
+        try {
+            $context = \context::instance_by_id($this->objectid);
+            $url = $context->get_url();
+        } catch (\dml_missing_record_exception $e) {
+            // The context no longer exists, give them the system url instead.
+            $url = \context_system::instance()->get_url();
+        }
+        return $url;
+    }
+
+    /**
+     * Init method.
+     *
+     * @return void
+     */
+    protected function init() {
+        $this->data['crud'] = 'u';
+        $this->data['edulevel'] = self::LEVEL_OTHER;
+        $this->data['objecttable'] = 'context';
+    }
+}
diff --git a/lib/tests/event_context_locked_test.php b/lib/tests/event_context_locked_test.php
new file mode 100644
index 00000000000..2a7a43532c8
--- /dev/null
+++ b/lib/tests/event_context_locked_test.php
@@ -0,0 +1,109 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Unit tests for the context locking events.
+ *
+ * @package    core
+ * @category   test
+ * @copyright  2019 University of Nottingham
+ * @author     Neill Magill <neill.magill@nottingham.ac.uk>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+use core\event\context_locked;
+use core\event\context_unlocked;
+
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * Unit tests for the context_locked  and context_unlocked events.
+ *
+ * @package    core
+ * @category   test
+ * @copyright  2019 University of Nottingham
+ * @author     Neill Magill <neill.magill@nottingham.ac.uk>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class core_event_context_locked_testcase extends \advanced_testcase {
+    /**
+     * Locks an unlocked context and checks that a core\event\context_locked event is created.
+     *
+     * @param \context $context
+     */
+    protected function lock_context(\context $context) {
+        self::assertFalse($context->is_locked());
+
+        $locksink = $this->redirectEvents();
+        $context->set_locked(true);
+        // This second call should not create an event as the lock status has not changed.
+        $context->set_locked(true);
+        $lockevents = $locksink->get_events();
+        $locksink->close();
+
+        self::assertCount(1, $lockevents);
+        self::assertContainsOnlyInstancesOf('core\event\context_locked', $lockevents);
+        self::assertEquals($context->id, $lockevents[0]->objectid);
+        $this->assertSame('context', $lockevents[0]->objecttable);
+        $this->assertEquals($context, $lockevents[0]->get_context());
+    }
+
+    /**
+     * Tests that events are created when contexts are locked and unlocked.
+     */
+    public function test_creation() {
+        $this->resetAfterTest();
+
+        $category = self::getDataGenerator()->create_category();
+        $catcontext = \context_coursecat::instance($category->id);
+        $course = self::getDataGenerator()->create_course(['category' => $category->id]);
+        $coursecontext = \context_course::instance($course->id);
+        $activitygenerator = self::getDataGenerator()->get_plugin_generator('mod_forum');
+        $activity = $activitygenerator->create_instance(['course' => $course->id]);
+        $activitycontext = \context_module::instance($activity->cmid);
+
+        $this->lock_context($catcontext);
+        $this->unlock_context($catcontext);
+
+        $this->lock_context($coursecontext);
+        $this->unlock_context($coursecontext);
+
+        $this->lock_context($activitycontext);
+        $this->unlock_context($activitycontext);
+    }
+
+    /**
+     * Unlocks a locked context and checks that a core\event\context_unlocked event is created.
+     *
+     * @param \context $context
+     */
+    protected function unlock_context(\context $context) {
+        self::assertTrue($context->is_locked());
+
+        $unlocksink = $this->redirectEvents();
+        $context->set_locked(false);
+        // This second call should not create an event as the lock status has not changed.
+        $context->set_locked(false);
+        $unlockevents = $unlocksink->get_events();
+        $unlocksink->close();
+
+        self::assertCount(1, $unlockevents);
+        self::assertContainsOnlyInstancesOf('core\event\context_unlocked', $unlockevents);
+        self::assertEquals($context->id, $unlockevents[0]->objectid);
+        $this->assertSame('context', $unlockevents[0]->objecttable);
+        $this->assertEquals($context, $unlockevents[0]->get_context());
+    }
+}