diff --git src/bp-loader.php src/bp-loader.php
index e73cbf9..9e6461d 100644
--- src/bp-loader.php
+++ src/bp-loader.php
@@ -259,7 +259,7 @@ class BuddyPress {
 					$plugins = get_site_option( 'active_sitewide_plugins');
 
 					// basename
-					$basename = basename( constant( 'BP_PLUGIN_DIR' ) ) . '/bp-loader.php';
+					$basename = plugin_basename( constant( 'BP_PLUGIN_DIR' ) . '/bp-loader.php' );
 
 					// plugin is network-activated; use main site ID instead
 					if ( isset( $plugins[ $basename ] ) ) {
@@ -358,7 +358,7 @@ class BuddyPress {
 
 		// BuddyPress root directory
 		$this->file           = constant( 'BP_PLUGIN_DIR' ) . 'bp-loader.php';
-		$this->basename       = basename( constant( 'BP_PLUGIN_DIR' ) ) . '/bp-loader.php';
+		$this->basename       = plugin_basename( constant( 'BP_PLUGIN_DIR' ) . '/bp-loader.php' );
 		$this->plugin_dir     = trailingslashit( constant( 'BP_PLUGIN_DIR' ) . constant( 'BP_SOURCE_SUBDIRECTORY' ) );
 		$this->plugin_url     = trailingslashit( constant( 'BP_PLUGIN_URL' ) . constant( 'BP_SOURCE_SUBDIRECTORY' ) );