diff --git a/browser/base/content/browser.js b/browser/base/content/browser.js
index 64f13ae3813f..9ea443cdf27c 100644
--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -823,7 +823,8 @@ var gBrowserInit = {
     // setup history swipe animation
     gHistorySwipeAnimation.init();
 
-    if (window.opener && !window.opener.closed) {
+    if (window.opener && !window.opener.closed &&
+        PrivateBrowsingUtils.isWindowPrivate(window) == PrivateBrowsingUtils.isWindowPrivate(window.opener)) {
       let openerSidebarBox = window.opener.document.getElementById("sidebar-box");
       // If the opener had a sidebar, open the same sidebar in our window.
       // The opener can be the hidden window too, if we're coming from the state
diff --git a/browser/components/privatebrowsing/test/browser/Makefile.in b/browser/components/privatebrowsing/test/browser/Makefile.in
index 5d31c3f71816..03be7c9562d0 100644
--- a/browser/components/privatebrowsing/test/browser/Makefile.in
+++ b/browser/components/privatebrowsing/test/browser/Makefile.in
@@ -45,6 +45,7 @@ MOCHITEST_BROWSER_FILES =  \
 		browser_privatebrowsing_popupblocker.js \
 		browser_privatebrowsing_protocolhandler.js \
 		browser_privatebrowsing_protocolhandler_page.html \
+    browser_privatebrowsing_sidebar.js \
 		browser_privatebrowsing_theming.js \
 		browser_privatebrowsing_ui.js \
 		browser_privatebrowsing_urlbarfocus.js \
diff --git a/browser/components/privatebrowsing/test/browser/browser_privatebrowsing_sidebar.js b/browser/components/privatebrowsing/test/browser/browser_privatebrowsing_sidebar.js
new file mode 100644
index 000000000000..7883f5d55df3
--- /dev/null
+++ b/browser/components/privatebrowsing/test/browser/browser_privatebrowsing_sidebar.js
@@ -0,0 +1,92 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This test makes sure that Sidebars do not migrate across windows with
+// different privacy states
+
+// See Bug 885054: https://bugzilla.mozilla.org/show_bug.cgi?id=885054
+
+function test() {
+  waitForExplicitFinish();
+
+  let { utils: Cu } = Components;
+
+  let { Promise: { defer } } = Cu.import("resource://gre/modules/Promise.jsm", {});
+
+  // opens a sidebar
+  function openSidebar(win) {
+    let { promise, resolve } = defer();
+    let doc = win.document;
+
+    let sidebarID = 'viewBookmarksSidebar';
+
+    let sidebar = doc.getElementById('sidebar');
+
+    let sidebarurl = doc.getElementById(sidebarID).getAttribute('sidebarurl');
+
+    sidebar.addEventListener('load', function onSidebarLoad() {
+      if (sidebar.contentWindow.location.href != sidebarurl)
+        return;
+      sidebar.removeEventListener('load', onSidebarLoad, true);
+
+      resolve(win);
+    }, true);
+
+    win.toggleSidebar(sidebarID, true);
+
+    return promise;
+  }
+
+  let windowCache = [];
+  function cacheWindow(w) {
+    windowCache.push(w);
+    return w;
+  }
+  function closeCachedWindows () {
+    windowCache.forEach(function(w) w.close());
+  }
+
+  // Part 1: NON PRIVATE WINDOW -> PRIVATE WINDOW
+  openWindow(window, {}, 1).
+    then(cacheWindow).
+    then(openSidebar).
+    then(function(win) openWindow(win, { private: true })).
+    then(cacheWindow).
+    then(function({ document }) {
+      let sidebarBox = document.getElementById("sidebar-box");
+      is(sidebarBox.hidden, true, 'Opening a private window from reg window does not open the sidebar');
+    }).
+    // Part 2: NON PRIVATE WINDOW -> NON PRIVATE WINDOW
+    then(function() openWindow(window)).
+    then(cacheWindow).
+    then(openSidebar).
+    then(function(win) openWindow(win)).
+    then(cacheWindow).
+    then(function({ document }) {
+      let sidebarBox = document.getElementById("sidebar-box");
+      is(sidebarBox.hidden, false, 'Opening a reg window from reg window does open the sidebar');
+    }).
+    // Part 3: PRIVATE WINDOW -> NON PRIVATE WINDOW
+    then(function() openWindow(window, { private: true })).
+    then(cacheWindow).
+    then(openSidebar).
+    then(function(win) openWindow(win)).
+    then(cacheWindow).
+    then(function({ document }) {
+      let sidebarBox = document.getElementById("sidebar-box");
+      is(sidebarBox.hidden, true, 'Opening a reg window from a private window does not open the sidebar');
+    }).
+    // Part 4: PRIVATE WINDOW -> PRIVATE WINDOW
+    then(function() openWindow(window, { private: true })).
+    then(cacheWindow).
+    then(openSidebar).
+    then(function(win) openWindow(win, { private: true })).
+    then(cacheWindow).
+    then(function({ document }) {
+      let sidebarBox = document.getElementById("sidebar-box");
+      is(sidebarBox.hidden, false, 'Opening a private window from private window does open the sidebar');
+    }).
+    then(closeCachedWindows).
+    then(finish);
+}
diff --git a/browser/components/privatebrowsing/test/browser/head.js b/browser/components/privatebrowsing/test/browser/head.js
index 9569a901f1bc..a34ec8bbfc8f 100644
--- a/browser/components/privatebrowsing/test/browser/head.js
+++ b/browser/components/privatebrowsing/test/browser/head.js
@@ -31,6 +31,20 @@ function whenNewWindowLoaded(aOptions, aCallback) {
   return win;
 }
 
+function openWindow(aParent, aOptions, a3) {
+  let { Promise: { defer } } = Components.utils.import("resource://gre/modules/Promise.jsm", {});
+  let { promise, resolve } = defer();
+
+  let win = aParent.OpenBrowserWindow(aOptions);
+
+  win.addEventListener("load", function onLoad() {
+    win.removeEventListener("load", onLoad, false);
+    resolve(win);
+  }, false);
+
+  return promise;
+}
+
 function newDirectory() {
   let FileUtils =
     Cu.import("resource://gre/modules/FileUtils.jsm", {}).FileUtils;
@@ -62,4 +76,3 @@ function _initTest() {
 }
 
 _initTest();
-