diff --git a/civicrm.php b/civicrm.php
index 6921266ad351d9c6ceaf8c0f34c5fc69ca56f2dd..f624cfd1dcaf0ee1e1e38c3919755aea000afc10 100644
--- a/civicrm.php
+++ b/civicrm.php
@@ -523,8 +523,10 @@ class CiviCRM_For_WordPress {
     include_once CIVICRM_PLUGIN_DIR . 'includes/civicrm.basepage.php';
     $this->basepage = new CiviCRM_For_WordPress_Basepage;
 
-    // Include REST API autoloader class
-    require_once( CIVICRM_PLUGIN_DIR . 'wp-rest/Autoloader.php' );
+    if ( ! class_exists( 'CiviCRM_WP_REST\Autoloader' ) ) {
+      // Include REST API autoloader class
+      require_once( CIVICRM_PLUGIN_DIR . 'wp-rest/Autoloader.php' );
+    }
 
   }
 
@@ -650,11 +652,15 @@ class CiviCRM_For_WordPress {
     // Register hooks for clean URLs.
     $this->register_hooks_clean_urls();
 
-    // Set up REST API.
-    CiviCRM_WP_REST\Autoloader::add_source( $source_path = trailingslashit( CIVICRM_PLUGIN_DIR . 'wp-rest' ) );
+    if ( ! class_exists( 'CiviCRM_WP_REST\Plugin' ) ) {
+
+      // Set up REST API.
+      CiviCRM_WP_REST\Autoloader::add_source( $source_path = trailingslashit( CIVICRM_PLUGIN_DIR . 'wp-rest' ) );
 
-    // Init REST API.
-    new CiviCRM_WP_REST\Plugin;
+      // Init REST API.
+      new CiviCRM_WP_REST\Plugin;
+
+    }
 
   }