diff --git a/mod/assign/locallib.php b/mod/assign/locallib.php
index 5c1775e239e..fe7700e616e 100644
--- a/mod/assign/locallib.php
+++ b/mod/assign/locallib.php
@@ -7162,6 +7162,10 @@ class assign {
         }
 
         $this->update_submission($newsubmission, $userid, false, $this->get_instance()->teamsubmission);
+        $flags = $this->get_user_flags($userid, false);
+        if ($flags->locked) {
+            $this->process_unlock_submission($userid);
+        }
         return true;
     }
 
diff --git a/mod/assign/tests/behat/reopen_locked_submission.feature b/mod/assign/tests/behat/reopen_locked_submission.feature
new file mode 100644
index 00000000000..8ecec3d7ff6
--- /dev/null
+++ b/mod/assign/tests/behat/reopen_locked_submission.feature
@@ -0,0 +1,86 @@
+@mod @mod_assign
+Feature: Submissions are unlocked when a new attempt is given
+  In order to allow students to reattempt a locked submission
+  As a teacher
+  I need to use quick grading to grant a new submission
+
+  Background:
+    Given the following "courses" exist:
+      | fullname | shortname | category | groupmode |
+      | Course 1 | C1 | 0 | 1 |
+    And the following "users" exist:
+      | username | firstname | lastname | email |
+      | teacher1 | Teacher | 1 | teacher1@example.com |
+      | student1 | Student | 1 | student1@example.com |
+    And the following "course enrolments" exist:
+      | user | course | role |
+      | teacher1 | C1 | editingteacher |
+      | student1 | C1 | student |
+
+  @javascript
+  Scenario: A locked submission should unlock when a new attempt is automatically given.
+    And I log in as "teacher1"
+    And I follow "Course 1"
+    And I turn editing mode on
+    And I add a "Assignment" to section "1" and I fill the form with:
+      | Assignment name | Test assignment name |
+      | Description | Submit your online text |
+      | assignsubmission_onlinetext_enabled | 1 |
+      | Attempts reopened | Automatically until pass |
+      | Grade to pass | 50 |
+    And I log out
+    And I log in as "student1"
+    And I follow "Course 1"
+    And I follow "Test assignment name"
+    And I press "Add submission"
+    And I set the following fields to these values:
+      | Online text | I'm the student1 submission |
+    And I press "Save changes"
+    And I log out
+    And I log in as "teacher1"
+    And I am on site homepage
+    And I follow "Course 1"
+    And I follow "Test assignment name"
+    And I follow "View/grade all submissions"
+    And I click on "Edit" "link" in the "Student 1" "table_row"
+    And I follow "Prevent submission changes"
+    And I should see "Submission changes not allowed"
+    And I click on "Quick grading" "checkbox"
+    And I set the field "User grade" to "49.0"
+    And I press "Save all quick grading changes"
+    And I should see "The grade changes were saved"
+    And I press "Continue"
+    Then I should see "Reopened"
+    And I should not see "Submission changes not allowed"
+
+  @javascript
+  Scenario: A locked submission should unlock when a new attempt is manually given.
+    And I log in as "teacher1"
+    And I follow "Course 1"
+    And I turn editing mode on
+    And I add a "Assignment" to section "1" and I fill the form with:
+      | Assignment name | Test assignment name |
+      | Description | Submit your online text |
+      | assignsubmission_onlinetext_enabled | 1 |
+      | Attempts reopened | Manually |
+    And I log out
+    And I log in as "student1"
+    And I follow "Course 1"
+    And I follow "Test assignment name"
+    And I press "Add submission"
+    And I set the following fields to these values:
+      | Online text | I'm the student1 submission |
+    And I press "Save changes"
+    And I log out
+    And I log in as "teacher1"
+    And I am on site homepage
+    And I follow "Course 1"
+    And I follow "Test assignment name"
+    And I follow "View/grade all submissions"
+    And I click on "Edit" "link" in the "Student 1" "table_row"
+    And I follow "Prevent submission changes"
+    And I should see "Submission changes not allowed"
+    And I click on "Edit" "link" in the "Student 1" "table_row"
+    And I follow "Allow another attempt"
+    Then I should see "Reopened"
+    And I should not see "Submission changes not allowed"
\ No newline at end of file