--- a/mobile/android/chrome/geckoview/geckoview.js
+++ b/mobile/android/chrome/geckoview/geckoview.js
@@ -58,16 +58,25 @@ var ModuleManager = {
     ]);
 
     this.messageManager.addMessageListener("GeckoView:ContentModuleLoaded",
                                            this);
 
     this.forEach(module => {
       module.onInit();
     });
+
+    window.addEventListener("unload", () => {
+      this.forEach(module => {
+        module.enabled = false;
+        module.onDestroy();
+      });
+
+      this._modules.clear();
+    });
   },
 
   get window() {
     return window;
   },
 
   get browser() {
     return this._browser;
@@ -195,16 +204,22 @@ class ModuleInfo {
       this._impl.onSettingsUpdate();
     }
     this._loadPhase(this._onInitPhase);
     this._onInitPhase = null;
 
     this.enabled = this._enabledOnInit;
   }
 
+  onDestroy() {
+    if (this._impl) {
+      this._impl.onDestroy();
+    }
+  }
+
   /**
    * Load resources according to a phase object that contains possible keys,
    *
    * "resource": specify the JSM resource to load for this module.
    * "frameScript": specify a content JS frame script to load for this module.
    */
   _loadPhase(aPhase) {
     if (!aPhase) {

--- a/mobile/android/modules/geckoview/GeckoViewModule.jsm
+++ b/mobile/android/modules/geckoview/GeckoViewModule.jsm
@@ -50,16 +50,19 @@ class GeckoViewModule {
   }
 
   // Override to initialize the browser before it is bound to the window.
   onInitBrowser() {}
 
   // Override to initialize module.
   onInit() {}
 
+  // Override to cleanup when the window is closed
+  onDestroy() {}
+
   // Override to detect settings change. Access settings via this.settings.
   onSettingsUpdate() {}
 
   // Override to enable module after setting a Java delegate.
   onEnable() {}
 
   // Override to disable module after clearing the Java delegate.
   onDisable() {}