diff --git a/message/classes/helper.php b/message/classes/helper.php
index 99ecdfabe4c..58dd7aa174e 100644
--- a/message/classes/helper.php
+++ b/message/classes/helper.php
@@ -589,6 +589,9 @@ class helper {
             }
         }
 
+        // Return member information in the same order as the userids originally provided.
+        $members = array_replace(array_flip($userids), $members);
+
         return $members;
     }
 
diff --git a/message/tests/helper_test.php b/message/tests/helper_test.php
new file mode 100644
index 00000000000..8de40f6493f
--- /dev/null
+++ b/message/tests/helper_test.php
@@ -0,0 +1,70 @@
+<?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/>.
+
+/**
+ * Contains a test class for the message helper.
+ *
+ * @package core_message
+ * @category test
+ * @copyright 2018 Jake Dallimore <jrhdallimore@gmail.com>
+ * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die();
+
+global $CFG;
+
+require_once($CFG->dirroot . '/message/tests/messagelib_test.php');
+
+/**
+ * Tests for the message helper class.
+ *
+ * @package core_message
+ * @category test
+ * @copyright 2018 Jake Dallimore <jrhdallimore@gmail.com>
+ * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class core_message_helper_testcase extends advanced_testcase {
+
+    public function setUp() {
+        $this->resetAfterTest(true);
+    }
+
+    public function test_get_member_info_ordering() {
+        // Create a conversation with several users.
+        $user1 = self::getDataGenerator()->create_user();
+        $user2 = self::getDataGenerator()->create_user();
+        $user3 = self::getDataGenerator()->create_user();
+        $user4 = self::getDataGenerator()->create_user();
+
+        \core_message\api::create_conversation(
+            \core_message\api::MESSAGE_CONVERSATION_TYPE_GROUP,
+            [
+                $user1->id,
+                $user2->id,
+                $user3->id,
+                $user4->id,
+            ],
+            'Group conversation'
+        );
+
+        // Verify that the member information comes back in the same order that we specified in the input array.
+        $memberinfo = \core_message\helper::get_member_info($user1->id, [$user3->id, $user4->id, $user2->id]);
+        $this->assertEquals($user3->id, array_shift($memberinfo)->id);
+        $this->assertEquals($user4->id, array_shift($memberinfo)->id);
+        $this->assertEquals($user2->id, array_shift($memberinfo)->id);
+    }
+}