diff --git a/webservice/externallib.php b/webservice/externallib.php
index e8e11de1649..4daf43473ed 100644
--- a/webservice/externallib.php
+++ b/webservice/externallib.php
@@ -206,6 +206,7 @@ class core_webservice_external extends external_api {
         } else {
             $siteinfo['usercalendartype'] = $USER->calendartype;
         }
+        $siteinfo['userissiteadmin'] = is_siteadmin();
 
         // User key, to avoid using the WS token for fetching assets.
         $siteinfo['userprivateaccesskey'] = get_user_key('core_files', $USER->id);
@@ -280,6 +281,7 @@ class core_webservice_external extends external_api {
                 '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),
+                'userissiteadmin'  => new external_value(PARAM_BOOL, 'Whether the user is a site admin or not.', 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 92fe1e48faa..fe56e750563 100644
--- a/webservice/tests/externallib_test.php
+++ b/webservice/tests/externallib_test.php
@@ -132,6 +132,7 @@ class core_webservice_externallib_testcase extends externallib_advanced_testcase
         } else {
             $this->assertEquals($CFG->calendartype, $siteinfo['usercalendartype']);
         }
+        $this->assertFalse($siteinfo['userissiteadmin']);
         $this->assertEquals($CFG->calendartype, $siteinfo['sitecalendartype']);
         $this->assertEquals($user['theme'], $siteinfo['theme']);
 
@@ -162,6 +163,7 @@ class core_webservice_externallib_testcase extends externallib_advanced_testcase
         $this->assertEquals(0, $siteinfo['userquota']);
         $this->assertEquals(USER_CAN_IGNORE_FILE_SIZE_LIMITS, $siteinfo['usermaxuploadfilesize']);
         $this->assertEquals(true, $siteinfo['usercanmanageownfiles']);
+        $this->assertTrue($siteinfo['userissiteadmin']);
         $this->assertEmpty($USER->theme);
         $this->assertEquals($PAGE->theme->name, $siteinfo['theme']);
     }
diff --git a/webservice/upgrade.txt b/webservice/upgrade.txt
index 14ce75e2423..6f92dd39f76 100644
--- a/webservice/upgrade.txt
+++ b/webservice/upgrade.txt
@@ -12,6 +12,8 @@ This information is intended for authors of webservices, not people writing webs
 * External function core_webservice_external::get_site_info() now returns the user private access key "userprivateaccesskey".
   This key could be used for fetching files via the tokenpluginfile.php script instead webservice/pluginfile.php to avoid
   multiple GET requests that include the WS token as a visible parameter.
+* External function core_webservice_external::get_site_info() now returns a new field "userissiteadmin" indicating if
+  the current user is a site administrator.
 
 === 3.7 ===