--- a/browser/base/content/browser-addons.js
+++ b/browser/base/content/browser-addons.js
@@ -159,35 +159,49 @@ const gXPInstallObserver = {
         messageString = messageString.replace("#4", Services.appinfo.version);
 
         PopupNotifications.show(browser, notificationID, messageString, anchorID,
                                 action, null, options);
       }
       this._removeProgressNotification(browser);
       break; }
     case "addon-install-confirmation": {
+      let unsigned = installInfo.installs.filter(i => i.addon.signedState <= AddonManager.SIGNEDSTATE_MISSING);
+      let someUnsigned = unsigned.length > 0 && unsigned.length < installInfo.installs.length;
+
       options.eventCallback = (aEvent) => {
         switch (aEvent) {
           case "removed":
             if (installInfo) {
               for (let install of installInfo.installs)
                 install.cancel();
             }
             this.acceptInstallation = null;
             break;
           case "shown":
             let addonList = document.getElementById("addon-install-confirmation-content");
             while (addonList.firstChild)
               addonList.firstChild.remove();
 
             for (let install of installInfo.installs) {
+              let container = document.createElement("hbox");
+
               let name = document.createElement("label");
               name.setAttribute("value", install.addon.name);
               name.setAttribute("class", "addon-install-confirmation-name");
-              addonList.appendChild(name);
+              container.appendChild(name);
+
+              if (someUnsigned && install.addon.signedState <= AddonManager.SIGNEDSTATE_MISSING) {
+                let unsigned = document.createElement("label");
+                unsigned.setAttribute("value", gNavigatorBundle.getString("addonInstall.unsigned"));
+                unsigned.setAttribute("class", "addon-install-confirmation-unsigned");
+                container.appendChild(unsigned);
+              }
+
+              addonList.appendChild(container);
             }
 
             this.acceptInstallation = () => {
               for (let install of installInfo.installs)
                 install.install();
               installInfo = null;
 
               Services.telemetry
@@ -196,17 +210,30 @@ const gXPInstallObserver = {
             };
             break;
         }
       };
 
       options.learnMoreURL = Services.urlFormatter.formatURLPref("app.support.baseURL") +
                              "find-and-install-add-ons";
 
-      messageString = gNavigatorBundle.getString("addonConfirmInstall.message");
+      if (unsigned.length == installInfo.installs.length) {
+        // None of the add-ons are verified
+        messageString = gNavigatorBundle.getString("addonConfirmInstallUnsigned.message");
+      }
+      else if (unsigned.length == 0) {
+        // All add-ons are verified or don't need to be verified
+        messageString = gNavigatorBundle.getString("addonConfirmInstall.message");
+      }
+      else {
+        // Some of the add-ons are unverified, the list of names will indicate
+        // which
+        messageString = gNavigatorBundle.getString("addonConfirmInstallSomeUnsigned.message");
+      }
+
       messageString = PluralForm.get(installInfo.installs.length, messageString);
       messageString = messageString.replace("#1", brandShortName);
       messageString = messageString.replace("#2", installInfo.installs.length);
 
       let cancelButton = document.getElementById("addon-install-confirmation-cancel");
       cancelButton.label = gNavigatorBundle.getString("addonInstall.cancelButton.label");
       cancelButton.accessKey = gNavigatorBundle.getString("addonInstall.cancelButton.accesskey");
 

--- a/browser/base/content/test/general/browser_bug553455.js
+++ b/browser/base/content/test/general/browser_bug553455.js
@@ -450,16 +450,120 @@ function test_multiple() {
   var triggers = encodeURIComponent(JSON.stringify({
     "Unsigned XPI": "unsigned.xpi",
     "Restartless XPI": "restartless.xpi"
   }));
   gBrowser.selectedTab = gBrowser.addTab();
   gBrowser.loadURI(TESTROOT + "installtrigger.html?" + triggers);
 },
 
+function test_someunverified() {
+  // This test is only relevant if using the new doorhanger UI and allowing
+  // unsigned add-ons
+  if (!Preferences.get("xpinstall.customConfirmationUI", false) ||
+      Preferences.get("xpinstall.signatures.required", true)) {
+    runNextTest();
+    return;
+  }
+
+  // Wait for the progress notification
+  wait_for_progress_notification(function(aPanel) {
+    // Wait for the install confirmation dialog
+    wait_for_install_dialog(function() {
+      let notification = document.getElementById("addon-install-confirmation-notification");
+      let message = notification.getAttribute("label");
+      is(message, "Caution: This site would like to install 2 add-ons in " + gApp + ", some of which are unverified. Proceed at your own risk.",
+         "Should see the right message");
+
+      let container = document.getElementById("addon-install-confirmation-content");
+      is(container.childNodes.length, 2, "Should be two items listed");
+      is(container.childNodes[0].firstChild.getAttribute("value"), "XPI Test", "Should have the right add-on");
+      is(container.childNodes[0].lastChild.getAttribute("class"),
+         "addon-install-confirmation-unsigned", "Should have the unverified marker");
+      is(container.childNodes[1].firstChild.getAttribute("value"), "Theme Test", "Should have the right add-on");
+      is(container.childNodes[1].childNodes.length, 1, "Shouldn't have the unverified marker");
+
+      // Wait for the complete notification
+      wait_for_notification("addon-install-complete", function(aPanel) {
+        AddonManager.getAddonsByIDs(["restartless-xpi@tests.mozilla.org",
+                                     "theme-xpi@tests.mozilla.org"], function([a, t]) {
+          a.uninstall();
+          // Installing a new theme tries to switch to it, switch back to the
+          // default theme.
+          t.userDisabled = true;
+          t.uninstall();
+
+          Services.perms.remove("example.com", "install");
+          wait_for_notification_close(runNextTest);
+          gBrowser.removeTab(gBrowser.selectedTab);
+        });
+      });
+
+      accept_install_dialog();
+    });
+  });
+
+  var pm = Services.perms;
+  pm.add(makeURI("http://example.com/"), "install", pm.ALLOW_ACTION);
+
+  var triggers = encodeURIComponent(JSON.stringify({
+    "Extension XPI": "restartless.xpi",
+    "Theme XPI": "theme.xpi"
+  }));
+  gBrowser.selectedTab = gBrowser.addTab();
+  gBrowser.loadURI(TESTROOT + "installtrigger.html?" + triggers);
+},
+
+function test_allunverified() {
+  // This test is only relevant if using the new doorhanger UI and allowing
+  // unsigned add-ons
+  if (!Preferences.get("xpinstall.customConfirmationUI", false) ||
+      Preferences.get("xpinstall.signatures.required", true)) {
+    runNextTest();
+    return;
+  }
+
+  // Wait for the progress notification
+  wait_for_progress_notification(function(aPanel) {
+    // Wait for the install confirmation dialog
+    wait_for_install_dialog(function() {
+      let notification = document.getElementById("addon-install-confirmation-notification");
+      let message = notification.getAttribute("label");
+      is(message, "Caution: This site would like to install an unverified add-on in " + gApp + ". Proceed at your own risk.");
+
+      let container = document.getElementById("addon-install-confirmation-content");
+      is(container.childNodes.length, 1, "Should be one item listed");
+      is(container.childNodes[0].firstChild.getAttribute("value"), "XPI Test", "Should have the right add-on");
+      is(container.childNodes[0].childNodes.length, 1, "Shouldn't have the unverified marker");
+
+      // Wait for the complete notification
+      wait_for_notification("addon-install-complete", function(aPanel) {
+        AddonManager.getAddonByID("restartless-xpi@tests.mozilla.org", function(aAddon) {
+          aAddon.uninstall();
+
+          Services.perms.remove("example.com", "install");
+          wait_for_notification_close(runNextTest);
+          gBrowser.removeTab(gBrowser.selectedTab);
+        });
+      });
+
+      accept_install_dialog();
+    });
+  });
+
+  var pm = Services.perms;
+  pm.add(makeURI("http://example.com/"), "install", pm.ALLOW_ACTION);
+
+  var triggers = encodeURIComponent(JSON.stringify({
+    "Extension XPI": "restartless.xpi"
+  }));
+  gBrowser.selectedTab = gBrowser.addTab();
+  gBrowser.loadURI(TESTROOT + "installtrigger.html?" + triggers);
+},
+
 function test_url() {
   // Wait for the progress notification
   wait_for_progress_notification(function(aPanel) {
     // Wait for the install confirmation dialog
     wait_for_install_dialog(function() {
       // Wait for the complete notification
       wait_for_notification("addon-install-complete", function(aPanel) {
         let notification = aPanel.childNodes[0];

--- a/browser/locales/en-US/chrome/browser/browser.properties
+++ b/browser/locales/en-US/chrome/browser/browser.properties
@@ -32,27 +32,36 @@ xpinstallDisabledButton.accesskey=n
 
 # LOCALIZATION NOTE (addonDownloadingAndVerifying):
 # Semicolon-separated list of plural forms. See:
 # http://developer.mozilla.org/en/docs/Localization_and_Plurals
 # Also see https://bugzilla.mozilla.org/show_bug.cgi?id=570012 for mockups
 addonDownloadingAndVerifying=Downloading and verifying add-on…;Downloading and verifying #1 add-ons…
 addonDownloadVerifying=Verifying
 
+addonInstall.unsigned=(Unverified)
 addonInstall.cancelButton.label=Cancel
 addonInstall.cancelButton.accesskey=C
 addonInstall.acceptButton.label=Install
 addonInstall.acceptButton.accesskey=I
 
-# LOCALIZATION NOTE (addonConfirmInstallMessage):
+# LOCALIZATION NOTE (addonConfirmInstallMessage,addonConfirmInstallUnsigned):
 # Semicolon-separated list of plural forms. See:
 # http://developer.mozilla.org/en/docs/Localization_and_Plurals
 # #1 is brandShortName
 # #2 is the number of add-ons being installed
 addonConfirmInstall.message=This site would like to install an add-on in #1:;This site would like to install #2 add-ons in #1:
+addonConfirmInstallUnsigned.message=Caution: This site would like to install an unverified add-on in #1. Proceed at your own risk.;Caution: This site would like to install #2 unverified add-ons in #1. Proceed at your own risk.
+
+# LOCALIZATION NOTE (addonConfirmInstallSomeUnsigned.message):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 is brandShortName
+# #2 is the total number of add-ons being installed (at least 2)
+addonConfirmInstallSomeUnsigned.message=;Caution: This site would like to install #2 add-ons in #1, some of which are unverified. Proceed at your own risk.
 
 addonwatch.slow=%1$S might be making %2$S run slowly
 addonwatch.disable.label=Disable %S
 addonwatch.ignoreSession.label=Ignore for now
 addonwatch.ignoreSession.accesskey=I
 addonwatch.ignorePerm.label=Ignore permanently
 addonwatch.ignorePerm.accesskey=p
 addonwatch.restart.message=To disable %1$S you must restart %2$S