diff --git a/webservice/externallib.php b/webservice/externallib.php
index 94e3858c0a057..8391df7b68f19 100644
--- a/webservice/externallib.php
+++ b/webservice/externallib.php
@@ -206,6 +206,9 @@ public static function get_site_info($serviceshortnames = array()) {
             $siteinfo['usercalendartype'] = $USER->calendartype;
         }
 
+        // Current theme.
+        $siteinfo['theme'] = clean_param($PAGE->theme->name, PARAM_THEME);  // We always clean to avoid problem with old sites.
+
         return $siteinfo;
     }
 
@@ -271,6 +274,7 @@ public static function get_site_info_returns() {
                 'siteid'  => new external_value(PARAM_INT, 'Site course ID', VALUE_OPTIONAL),
                 'sitecalendartype'  => new external_value(PARAM_PLUGIN, 'Calendar type set in the site.', VALUE_OPTIONAL),
                 'usercalendartype'  => new external_value(PARAM_PLUGIN, 'Calendar typed used by the user.', VALUE_OPTIONAL),
+                'theme'  => new external_value(PARAM_THEME, 'Current theme for the user.', VALUE_OPTIONAL),
             )
         );
     }
diff --git a/webservice/tests/externallib_test.php b/webservice/tests/externallib_test.php
index f9122c67bebc7..91ffdfa4a7731 100644
--- a/webservice/tests/externallib_test.php
+++ b/webservice/tests/externallib_test.php
@@ -39,7 +39,7 @@ public function setUp() {
     }
 
     public function test_get_site_info() {
-        global $DB, $USER, $CFG;
+        global $DB, $USER, $CFG, $PAGE;
 
         $this->resetAfterTest(true);
 
@@ -49,10 +49,12 @@ public function test_get_site_info() {
         set_config('userquota', $userquota);
 
         // Set current user
+        set_config('allowuserthemes', 1);
         $user = array();
         $user['username'] = 'johnd';
         $user['firstname'] = 'John';
         $user['lastname'] = 'Doe';
+        $user['theme'] = 'more';
         self::setUser(self::getDataGenerator()->create_user($user));
 
         // Add a web service and token.
@@ -128,6 +130,8 @@ public function test_get_site_info() {
         } else {
             $this->assertEquals($CFG->calendartype, $siteinfo['usercalendartype']);
         }
+        $this->assertEquals($CFG->calendartype, $siteinfo['sitecalendartype']);
+        $this->assertEquals($user['theme'], $siteinfo['theme']);
 
         // Now as admin.
         $this->setAdminUser();
@@ -156,9 +160,8 @@ public function test_get_site_info() {
         $this->assertEquals(0, $siteinfo['userquota']);
         $this->assertEquals(USER_CAN_IGNORE_FILE_SIZE_LIMITS, $siteinfo['usermaxuploadfilesize']);
         $this->assertEquals(true, $siteinfo['usercanmanageownfiles']);
-
-        $this->assertEquals(HOMEPAGE_SITE, $siteinfo['userhomepage']);
-
+        $this->assertEmpty($USER->theme);
+        $this->assertEquals($PAGE->theme->name, $siteinfo['theme']);
     }
 
     /**
diff --git a/webservice/upgrade.txt b/webservice/upgrade.txt
index 8867faead4a79..d5b959d5c5ae5 100644
--- a/webservice/upgrade.txt
+++ b/webservice/upgrade.txt
@@ -3,6 +3,10 @@ information provided here is intended especially for developers.
 
 This information is intended for authors of webservices, not people writing webservice clients.
 
+=== 3.7 ===
+
+* External function core_webservice_external::get_site_info() now returns the current site theme (for the user).
+
 === 3.4 ===
 
 * External function core_webservice_external::get_site_info() now returns the calendar type used in the site and