diff --git a/tag-dropdown-widget.php b/tag-dropdown-widget.php
index 97dbece6ccad6ae824d452e899edd34e5bfa35a6..a287a0781737641d06c6d7e4cc9c67fdfe928f3d 100644
--- a/tag-dropdown-widget.php
+++ b/tag-dropdown-widget.php
@@ -92,7 +92,7 @@ class taxonomy_dropdown_widget_plugin {
 	 * @hook deactivation
 	 * @return null
 	 */
-	public deactivation_hook() {
+	public function deactivation_hook() {
 		$this->cleanup();
 	}