--- a/browser/components/nsBrowserGlue.js
+++ b/browser/components/nsBrowserGlue.js
@@ -310,17 +310,19 @@ BrowserGlue.prototype = {
   _saveSession: false,
   _migrationImportsDefaultBookmarks: false,
   _placesBrowserInitComplete: false,
 
   _setPrefToSaveSession: function BG__setPrefToSaveSession(aForce) {
     if (!this._saveSession && !aForce)
       return;
 
-    Services.prefs.setBoolPref("browser.sessionstore.resume_session_once", true);
+    if (!PrivateBrowsingUtils.permanentPrivateBrowsing) {
+      Services.prefs.setBoolPref("browser.sessionstore.resume_session_once", true);
+    }
 
     // This method can be called via [NSApplication terminate:] on Mac, which
     // ends up causing prefs not to be flushed to disk, so we need to do that
     // explicitly here. See bug 497652.
     Services.prefs.savePrefFile(null);
   },
 
   _setSyncAutoconnectDelay: function BG__setSyncAutoconnectDelay() {

--- a/browser/components/sessionstore/SessionStore.jsm
+++ b/browser/components/sessionstore/SessionStore.jsm
@@ -1714,17 +1714,20 @@ var SessionStoreInternal = {
 
   /**
    * On quitting application
    * @param aData
    *        String type of quitting
    */
   onQuitApplication: function ssi_onQuitApplication(aData) {
     if (aData == "restart") {
-      this._prefBranch.setBoolPref("sessionstore.resume_session_once", true);
+      if (!PrivateBrowsingUtils.permanentPrivateBrowsing) {
+        this._prefBranch.setBoolPref("sessionstore.resume_session_once", true);
+      }
+
       // The browser:purge-session-history notification fires after the
       // quit-application notification so unregister the
       // browser:purge-session-history notification to prevent clearing
       // session data on disk on a restart.  It is also unnecessary to
       // perform any other sanitization processing on a restart as the
       // browser is about to exit anyway.
       Services.obs.removeObserver(this, "browser:purge-session-history");
     }

--- a/browser/components/sessionstore/nsSessionStartup.js
+++ b/browser/components/sessionstore/nsSessionStartup.js
@@ -291,16 +291,20 @@ SessionStartup.prototype = {
   /**
    * Determines whether automatic session restoration is enabled for this
    * launch of the browser. This does not include crash restoration. In
    * particular, if session restore is configured to restore only in case of
    * crash, this method returns false.
    * @returns bool
    */
   isAutomaticRestoreEnabled() {
+    if (PrivateBrowsingUtils.permanentPrivateBrowsing) {
+      return false;
+    }
+
     return Services.prefs.getBoolPref("browser.sessionstore.resume_session_once") ||
            Services.prefs.getIntPref("browser.startup.page") == BROWSER_STARTUP_RESUME_SESSION;
   },
 
   /**
    * Determines whether there is a pending session restore.
    * @returns bool
    */