--- a/toolkit/mozapps/extensions/internal/XPIProvider.jsm
+++ b/toolkit/mozapps/extensions/internal/XPIProvider.jsm
@@ -7345,16 +7345,21 @@ AddonWrapper.prototype = {
 
     if (addon.inDatabase) {
       if (addon.type == "theme" && val) {
         if (addon.internalName == XPIProvider.defaultSkin)
           throw new Error("Cannot disable the default theme");
         XPIProvider.enableDefaultTheme();
       }
       else {
+        // hidden and system add-ons should not be user disasbled,
+        // as there is no UI to re-enable them.
+        if (this.hidden) {
+          throw new Error(`Cannot disable hidden add-on ${addon.id}`);
+        }
         XPIProvider.updateAddonDisabledState(addon, val);
       }
     }
     else {
       addon.userDisabled = val;
       // When enabling remove the softDisabled flag
       if (!val)
         addon.softDisabled = false;

new file mode 100644
--- /dev/null
+++ b/toolkit/mozapps/extensions/test/xpcshell/test_nodisable_hidden.js
@@ -0,0 +1,107 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+// This test verifies that hidden add-ons cannot be user disabled.
+
+// for normal add-ons
+const profileDir = FileUtils.getDir("ProfD", ["extensions"]);
+// for system add-ons
+const distroDir = FileUtils.getDir("ProfD", ["sysfeatures"], true);
+registerDirectory("XREAppFeat", distroDir);
+
+const NORMAL_ID = "normal@tests.mozilla.org";
+const SYSTEM_ID = "system@tests.mozilla.org";
+
+createAppInfo("xpcshell@tests.mozilla.org", "XPCShell", "1", "42");
+
+// normal add-ons can be user disabled.
+add_task(function*() {
+
+  writeInstallRDFToDir({
+    id: NORMAL_ID,
+    version: "1.0",
+    bootstrap: true,
+    targetApplications: [{
+      id: "xpcshell@tests.mozilla.org",
+      minVersion: "1",
+      maxVersion: "1"
+    }],
+    name: "Test disabling hidden add-ons, non-hidden add-on case.",
+  }, profileDir, NORMAL_ID);
+
+  startupManager();
+
+  let addon = yield promiseAddonByID(NORMAL_ID);
+  do_check_neq(addon, null);
+  do_check_eq(addon.version, "1.0");
+  do_check_eq(addon.name, "Test disabling hidden add-ons, non-hidden add-on case.");
+  do_check_true(addon.isCompatible);
+  do_check_false(addon.appDisabled);
+  do_check_false(addon.userDisabled);
+  do_check_true(addon.isActive);
+  do_check_eq(addon.type, "extension");
+
+  // normal add-ons can be disabled by the user.
+  addon.userDisabled = true;
+
+  do_check_neq(addon, null);
+  do_check_eq(addon.version, "1.0");
+  do_check_eq(addon.name, "Test disabling hidden add-ons, non-hidden add-on case.");
+  do_check_true(addon.isCompatible);
+  do_check_false(addon.appDisabled);
+  do_check_true(addon.userDisabled);
+  do_check_false(addon.isActive);
+  do_check_eq(addon.type, "extension");
+
+  addon.uninstall();
+
+  shutdownManager();
+});
+
+// system add-ons can never be user disabled.
+add_task(function*() {
+
+  writeInstallRDFToDir({
+    id: SYSTEM_ID,
+    version: "1.0",
+    bootstrap: true,
+    targetApplications: [{
+      id: "xpcshell@tests.mozilla.org",
+      minVersion: "1",
+      maxVersion: "1"
+    }],
+    name: "Test disabling hidden add-ons, hidden system add-on case.",
+  }, distroDir, SYSTEM_ID);
+
+  startupManager();
+
+  let addon = yield promiseAddonByID(SYSTEM_ID);
+  do_check_neq(addon, null);
+  do_check_eq(addon.version, "1.0");
+  do_check_eq(addon.name, "Test disabling hidden add-ons, hidden system add-on case.");
+  do_check_true(addon.isCompatible);
+  do_check_false(addon.appDisabled);
+  do_check_false(addon.userDisabled);
+  do_check_true(addon.isActive);
+  do_check_eq(addon.type, "extension");
+
+  // system add-ons cannot be disabled by the user.
+  try {
+    addon.userDisabled = true;
+    do_throw("Expected addon.userDisabled on a hidden add-on to throw!");
+  } catch(e) {
+    do_check_eq(e.message, `Cannot disable hidden add-on ${SYSTEM_ID}`);
+  }
+
+  do_check_neq(addon, null);
+  do_check_eq(addon.version, "1.0");
+  do_check_eq(addon.name, "Test disabling hidden add-ons, hidden system add-on case.");
+  do_check_true(addon.isCompatible);
+  do_check_false(addon.appDisabled);
+  do_check_false(addon.userDisabled);
+  do_check_true(addon.isActive);
+  do_check_eq(addon.type, "extension");
+
+  shutdownManager();
+});

--- a/toolkit/mozapps/extensions/test/xpcshell/xpcshell.ini
+++ b/toolkit/mozapps/extensions/test/xpcshell/xpcshell.ini
@@ -32,11 +32,12 @@ skip-if = appname != "firefox"
 [test_system_reset.js]
 [test_XPIcancel.js]
 [test_XPIStates.js]
 [test_temporary.js]
 [test_proxies.js]
 [test_proxy.js]
 [test_pass_symbol.js]
 [test_delay_update.js]
+[test_nodisable_hidden.js]
 
 
 [include:xpcshell-shared.ini]