diff --git a/user/classes/fields.php b/user/classes/fields.php
index f5ac4e7676e..2e7d94ad5eb 100644
--- a/user/classes/fields.php
+++ b/user/classes/fields.php
@@ -16,6 +16,8 @@
 
 namespace core_user;
 
+use core_text;
+
 /**
  * Class for retrieving information about user fields that are needed for displaying user identity.
  *
@@ -345,7 +347,8 @@ class fields {
      * showing lists of users (in addition to the user's name which is included as standard).
      *
      * The results include basic field names (columns from the 'user' database table) and, unless
-     * turned off, custom profile field names in the format 'profile_field_myfield'.
+     * turned off, custom profile field names in the format 'profile_field_myfield', note these
+     * fields will always be returned lower cased to match how they are returned by the DML library.
      *
      * This function does all the required capability checks to see if the current user is allowed
      * to see them in the specified context. You can pass context null to get all the fields
@@ -419,7 +422,7 @@ class fields {
 
         // Re-index the entries and return.
         $extra = array_values($extra);
-        return $extra;
+        return array_map([core_text::class, 'strtolower'], $extra);
     }
 
     /**
@@ -536,7 +539,8 @@ class fields {
                     $placeholder = '?';
                     $params[] = $shortname;
                 }
-                $joins .= " JOIN {user_info_field} $fieldalias ON $fieldalias.shortname = $placeholder
+                $joins .= " JOIN {user_info_field} $fieldalias ON " .
+                                 $DB->sql_equal($fieldalias . '.shortname', $placeholder, false) . "
                        LEFT JOIN {user_info_data} $dataalias ON $dataalias.fieldid = $fieldalias.id
                                  AND $dataalias.userid = {$usertable}id";
                 // For Oracle we need to convert the field into a usable format.
@@ -587,7 +591,7 @@ class fields {
         // Custom fields have special handling.
         if (preg_match(self::PROFILE_FIELD_REGEX, $field, $matches)) {
             require_once($CFG->dirroot . '/user/profile/lib.php');
-            $fieldinfo = profile_get_custom_field_data_by_shortname($matches[1]);
+            $fieldinfo = profile_get_custom_field_data_by_shortname($matches[1], false);
             // Use format_string so it can be translated with multilang filter if necessary.
             return $fieldinfo ? format_string($fieldinfo->name) : $field;
         }
diff --git a/user/profile/lib.php b/user/profile/lib.php
index d4b59d44e86..114089039c2 100644
--- a/user/profile/lib.php
+++ b/user/profile/lib.php
@@ -854,9 +854,11 @@ function profile_save_custom_fields($userid, $profilefields) {
  * current request for all fields so that it can be used quickly.
  *
  * @param string $shortname Shortname of custom profile field
+ * @param bool $casesensitive Whether to perform case-sensitive matching of shortname. Note current limitations of custom profile
+ *  fields allow the same shortname to exist differing only by it's case
  * @return stdClass|null Object with properties id, shortname, name, visible, datatype, categoryid, etc
  */
-function profile_get_custom_field_data_by_shortname(string $shortname): ?stdClass {
+function profile_get_custom_field_data_by_shortname(string $shortname, bool $casesensitive = true): ?stdClass {
     $cache = \cache::make_from_params(cache_store::MODE_REQUEST, 'core_profile', 'customfields',
             [], ['simplekeys' => true, 'simpledata' => true]);
     $data = $cache->get($shortname);
@@ -866,7 +868,13 @@ function profile_get_custom_field_data_by_shortname(string $shortname): ?stdClas
         $data = null;
         foreach ($fields as $field) {
             $cache->set($field->shortname, $field);
-            if ($field->shortname === $shortname) {
+
+            // Perform comparison according to case sensitivity parameter.
+            $shortnamematch = $casesensitive
+                ? strcmp($field->shortname, $shortname) === 0
+                : strcasecmp($field->shortname, $shortname) === 0;
+
+            if ($shortnamematch) {
                 $data = $field;
             }
         }
diff --git a/user/tests/profilelib_test.php b/user/tests/profilelib_test.php
index 77da39879f1..a49dc6bae81 100644
--- a/user/tests/profilelib_test.php
+++ b/user/tests/profilelib_test.php
@@ -283,4 +283,59 @@ class core_user_profilelib_testcase extends advanced_testcase {
 
         $this->assertNull(profile_get_custom_field_data_by_shortname('speciality'));
     }
+
+    /**
+     * Data provider for {@see test_profile_get_custom_field_data_by_shortname_case_sensitivity}
+     *
+     * @return array[]
+     */
+    public function profile_get_custom_field_data_by_shortname_case_sensitivity_provider(): array {
+        return [
+            'Matching case, case-sensitive search' => ['hello', 'hello', true, true],
+            'Matching case, case-insensitive search' => ['hello', 'hello', false, true],
+            'Non-matching case, case-sensitive search' => ['hello', 'Hello', true, false],
+            'Non-matching case, case-insensitive search' => ['hello', 'Hello', false, true],
+            'Non-matching, case-sensitive search' => ['hello', 'hola', true, false],
+            'Non-matching, case-insensitive search' => ['hello', 'hola', false, false],
+        ];
+    }
+
+    /**
+     * Test retrieving custom field by shortname, specifying case-sensitivity when matching
+     *
+     * @param string $shortname
+     * @param string $shortnamesearch
+     * @param bool $casesensitive
+     * @param bool $expectmatch
+     *
+     * @dataProvider profile_get_custom_field_data_by_shortname_case_sensitivity_provider
+     */
+    public function test_profile_get_custom_field_data_by_shortname_case_sensitivity(
+        string $shortname,
+        string $shortnamesearch,
+        bool $casesensitive,
+        bool $expectmatch
+    ): void {
+        global $CFG;
+
+        require_once("{$CFG->dirroot}/user/profile/lib.php");
+
+        $this->resetAfterTest();
+
+        $this->getDataGenerator()->create_custom_profile_field([
+            'datatype' => 'text',
+            'shortname' => $shortname,
+            'name' => 'My field',
+        ]);
+
+        $customfield = profile_get_custom_field_data_by_shortname($shortnamesearch, $casesensitive);
+        if ($expectmatch) {
+            $this->assertInstanceOf(\stdClass::class, $customfield);
+            $this->assertEquals('text', $customfield->datatype);
+            $this->assertEquals($shortname, $customfield->shortname);
+            $this->assertEquals('My field', $customfield->name);
+        } else {
+            $this->assertNull($customfield);
+        }
+    }
 }
diff --git a/user/upgrade.txt b/user/upgrade.txt
index d20af1afffd..bb08d441d75 100644
--- a/user/upgrade.txt
+++ b/user/upgrade.txt
@@ -1,5 +1,10 @@
 This files describes API changes for code that uses the user API.
 
+=== 3.11.5 ===
+
+* The `profile_get_custom_field_data_by_shortname` method now accepts an optional parameter to determine whether
+  to use case-sensitive matching of the profile field shortname or not (default true)
+
 === 3.11 ===
 
 * Added new core_user/form_user_selector JS module that can be used as the 'ajax' handler for the autocomplete form