diff --git a/toolkit/mozapps/extensions/addonManager.js b/toolkit/mozapps/extensions/addonManager.js
index 02a1f98e7ee9..942652d8a815 100644
--- a/toolkit/mozapps/extensions/addonManager.js
+++ b/toolkit/mozapps/extensions/addonManager.js
@@ -243,6 +243,7 @@ amManager.prototype = {
               onInstalled: (addon) => handler("onInstalled", addon.id, false),
               onUninstalling: (addon, needsRestart) => handler("onUninstalling", addon.id, needsRestart),
               onUninstalled: (addon) => handler("onUninstalled", addon.id, false),
+              onOperationCancelled: (addon) => handler("onOperationCancelled", addon.id, false),
             };
           }
           AddonManager.addAddonListener(this.addonListener);
diff --git a/toolkit/mozapps/extensions/test/browser/browser_webapi_addon_listener.js b/toolkit/mozapps/extensions/test/browser/browser_webapi_addon_listener.js
index 2bf9406c76c8..b8049f13cde1 100644
--- a/toolkit/mozapps/extensions/test/browser/browser_webapi_addon_listener.js
+++ b/toolkit/mozapps/extensions/test/browser/browser_webapi_addon_listener.js
@@ -18,6 +18,7 @@ const RESTART_ID = "restart@tests.mozilla.org";
 const RESTART_DISABLED_ID = "restart_disabled@tests.mozilla.org";
 const RESTARTLESS_ID = "restartless@tests.mozilla.org";
 const INSTALL_ID = "install@tests.mozilla.org";
+const CANCEL_ID = "cancel@tests.mozilla.org";
 
 let provider = new MockProvider(false);
 provider.createAddons([
@@ -35,6 +36,10 @@ provider.createAddons([
     name: "Restartless add-on",
     operationsRequiringRestart: AddonManager.OP_NEED_RESTART_NONE,
   },
+  {
+    id: CANCEL_ID,
+    name: "Add-on for uninstall cancel",
+  },
 ]);
 
 // Test disable of add-on requiring restart
@@ -145,3 +150,25 @@ add_task(function* test_uninstall() {
     Assert.deepEqual(events, expected, "Got expected uninstall events");
   });
 });
+
+// Test cancel of uninstall.
+add_task(function* test_cancel() {
+  yield BrowserTestUtils.withNewTab(TESTPAGE, function*(browser) {
+    let addon = yield promiseAddonByID(CANCEL_ID);
+    isnot(addon, null, "Found add-on for cancelling uninstall");
+
+    addon.uninstall();
+
+    let events = yield getListenerEvents(browser);
+    let expected = [
+      {id: CANCEL_ID, needsRestart: true, event: "onUninstalling"},
+    ];
+    Assert.deepEqual(events, expected, "Got expected uninstalling event");
+
+    addon.cancelUninstall();
+    events = yield getListenerEvents(browser);
+    expected.push({id: CANCEL_ID, needsRestart: false, event: "onOperationCancelled"});
+    Assert.deepEqual(events, expected, "Got expected cancel event");
+  });
+});
+
diff --git a/toolkit/mozapps/extensions/test/browser/webapi_addon_listener.html b/toolkit/mozapps/extensions/test/browser/webapi_addon_listener.html
index 05da5fb8c142..241779bda79c 100644
--- a/toolkit/mozapps/extensions/test/browser/webapi_addon_listener.html
+++ b/toolkit/mozapps/extensions/test/browser/webapi_addon_listener.html
@@ -14,6 +14,7 @@ let resultEl = document.getElementById("result");
   "onInstalled",
   "onUninstalling",
   "onUninstalled",
+  "onOperationCancelled",
 ].forEach(event => {
   navigator.mozAddonManager.addEventListener(event, data => {
     let obj = {event, id: data.id, needsRestart: data.needsRestart};