--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -4668,16 +4668,17 @@ pref("font.name-list.monospace.x-unicode
 
 # AIX
 #endif
 
 // Login Manager prefs
 pref("signon.rememberSignons",              true);
 pref("signon.rememberSignons.visibilityToggle", true);
 pref("signon.autofillForms",                true);
+pref("signon.autofillForms.autocompleteOff", true);
 pref("signon.autofillForms.http",           false);
 pref("signon.autologin.proxy",              false);
 pref("signon.formlessCapture.enabled",      true);
 pref("signon.privateBrowsingCapture.enabled", false);
 pref("signon.storeWhenAutocompleteOff",     true);
 pref("signon.debug",                        false);
 pref("signon.recipes.path",                 "chrome://passwordmgr/content/recipes.json");
 pref("signon.schemeUpgrades",               false);

--- a/toolkit/components/passwordmgr/LoginHelper.jsm
+++ b/toolkit/components/passwordmgr/LoginHelper.jsm
@@ -35,16 +35,17 @@ var LoginHelper = {
   init() {
     // Watch for pref changes to update cached pref values.
     Services.prefs.addObserver("signon.", () => this.updateSignonPrefs());
     this.updateSignonPrefs();
   },
 
   updateSignonPrefs() {
     this.autofillForms = Services.prefs.getBoolPref("signon.autofillForms");
+    this.autocompleteOff = Services.prefs.getBoolPref("signon.autofillForms.autocompleteOff");
     this.debug = Services.prefs.getBoolPref("signon.debug");
     this.enabled = Services.prefs.getBoolPref("signon.rememberSignons");
     this.formlessCaptureEnabled = Services.prefs.getBoolPref("signon.formlessCapture.enabled");
     this.insecureAutofill = Services.prefs.getBoolPref("signon.autofillForms.http");
     this.privateBrowsingCaptureEnabled =
       Services.prefs.getBoolPref("signon.privateBrowsingCapture.enabled");
 
     this.schemeUpgrades = Services.prefs.getBoolPref("signon.schemeUpgrades");

--- a/toolkit/components/passwordmgr/LoginManagerContent.jsm
+++ b/toolkit/components/passwordmgr/LoginManagerContent.jsm
@@ -1114,17 +1114,16 @@ var LoginManagerContent = {
     clobberPassword = false,
     userTriggered = false,
   } = {}) {
     if (ChromeUtils.getClassName(form) === "HTMLFormElement") {
       throw new Error("_fillForm should only be called with FormLike objects");
     }
 
     log("_fillForm", form.elements);
-    let ignoreAutocomplete = true;
     // Will be set to one of AUTOFILL_RESULT in the `try` block.
     let autofillResult = -1;
     const AUTOFILL_RESULT = {
       FILLED: 0,
       NO_PASSWORD_FIELD: 1,
       PASSWORD_DISABLED_READONLY: 2,
       NO_LOGINS_FIT: 3,
       NO_SAVED_LOGINS: 4,
@@ -1206,23 +1205,16 @@ var LoginManagerContent = {
       // Prevent autofilling insecure forms.
       if (!userTriggered && !LoginHelper.insecureAutofill &&
           !InsecurePasswordUtils.isFormSecure(form)) {
         log("not filling form since it's insecure");
         autofillResult = AUTOFILL_RESULT.INSECURE;
         return;
       }
 
-      var isAutocompleteOff = false;
-      if (this._isAutocompleteDisabled(form) ||
-          this._isAutocompleteDisabled(usernameField) ||
-          this._isAutocompleteDisabled(passwordField)) {
-        isAutocompleteOff = true;
-      }
-
       // Discard logins which have username/password values that don't
       // fit into the fields (as specified by the maxlength attribute).
       // The user couldn't enter these values anyway, and it helps
       // with sites that have an extra PIN to be entered (bug 391514)
       var maxUsernameLen = Number.MAX_VALUE;
       var maxPasswordLen = Number.MAX_VALUE;
 
       // If attribute wasn't set, default is -1.
@@ -1244,19 +1236,21 @@ var LoginManagerContent = {
       }, this);
 
       if (logins.length == 0) {
         log("form not filled, none of the logins fit in the field");
         autofillResult = AUTOFILL_RESULT.NO_LOGINS_FIT;
         return;
       }
 
+      const passwordACFieldName = passwordField.getAutocompleteInfo().fieldName;
+
       // If the password field has the autocomplete value of "new-password"
       // and we're autofilling without user interaction, there's nothing to do.
-      if (!userTriggered && passwordField.getAutocompleteInfo().fieldName == "new-password") {
+      if (!userTriggered && passwordACFieldName == "new-password") {
         log("not filling form, password field has the autocomplete new-password value");
         autofillResult = AUTOFILL_RESULT.PASSWORD_AUTOCOMPLETE_NEW_PASSWORD;
         return;
       }
 
       // Don't clobber an existing password.
       if (passwordField.value && !clobberPassword) {
         log("form not filled, the password field was already filled");
@@ -1317,26 +1311,28 @@ var LoginManagerContent = {
       // We will always have a selectedLogin at this point.
 
       if (!autofillForm) {
         log("autofillForms=false but form can be filled");
         autofillResult = AUTOFILL_RESULT.NO_AUTOFILL_FORMS;
         return;
       }
 
-      if (isAutocompleteOff && !ignoreAutocomplete) {
-        log("Not filling the login because we're respecting autocomplete=off");
+      if (!userTriggered &&
+          passwordACFieldName == "off" &&
+          !LoginHelper.autocompleteOff) {
+        log("Not autofilling the login because we're respecting autocomplete=off");
         autofillResult = AUTOFILL_RESULT.AUTOCOMPLETE_OFF;
         return;
       }
 
       // Fill the form
 
       if (usernameField) {
-      // Don't modify the username field if it's disabled or readOnly so we preserve its case.
+        // Don't modify the username field if it's disabled or readOnly so we preserve its case.
         let disabledOrReadOnly = usernameField.disabled || usernameField.readOnly;
 
         let userNameDiffers = selectedLogin.username != usernameField.value;
         // Don't replace the username if it differs only in case, and the user triggered
         // this autocomplete. We assume that if it was user-triggered the entered text
         // is desired.
         let userEnteredDifferentCase = userTriggered && userNameDiffers &&
                usernameField.value.toLowerCase() == selectedLogin.username.toLowerCase();

--- a/toolkit/components/passwordmgr/test/mochitest/mochitest.ini
+++ b/toolkit/components/passwordmgr/test/mochitest/mochitest.ini
@@ -46,16 +46,19 @@ skip-if = toolkit == 'android' # autocom
 [test_basic_form_0pw.html]
 [test_basic_form_1pw.html]
 [test_basic_form_1pw_2.html]
 [test_basic_form_2pw_1.html]
 [test_basic_form_2pw_2.html]
 [test_basic_form_3pw_1.html]
 [test_basic_form_autocomplete.html]
 skip-if = toolkit == 'android' # android:autocomplete.
+[test_basic_form_honor_autocomplete_off.html]
+scheme = https
+skip-if = toolkit == 'android' # android:autocomplete.
 [test_insecure_form_field_autocomplete.html]
 skip-if = toolkit == 'android' || os == 'linux' # android:autocomplete., linux: bug 1325778
 [test_password_field_autocomplete.html]
 skip-if = toolkit == 'android' # android:autocomplete.
 [test_insecure_form_field_no_saved_login.html]
 skip-if = toolkit == 'android' # android:autocomplete.
 [test_basic_form_html5.html]
 [test_basic_form_pwevent.html]

new file mode 100644
--- /dev/null
+++ b/toolkit/components/passwordmgr/test/mochitest/test_basic_form_honor_autocomplete_off.html
@@ -0,0 +1,167 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>Test login autofill autocomplete when signon.autofillForms.autocompleteOff is false</title>
+  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script type="text/javascript" src="/tests/SimpleTest/EventUtils.js"></script>
+  <script type="text/javascript" src="/tests/SimpleTest/AddTask.js"></script>
+  <script type="text/javascript" src="../../../satchel/test/satchel_common.js"></script>
+  <script type="text/javascript" src="pwmgr_common.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+Login Manager test: autofilling when autocomplete=off
+
+<script>
+const chromeScript = runChecksAfterCommonInit();
+
+const setupScript = runInParent(function setup() {
+  const {Services} = ChromeUtils.import("resource://gre/modules/Services.jsm");
+
+  // Create some logins just for this form, since we'll be deleting them.
+  const nsLoginInfo = Components.Constructor("@mozilla.org/login-manager/loginInfo;1",
+                                             Ci.nsILoginInfo, "init");
+  assert.ok(nsLoginInfo != null, "nsLoginInfo constructor");
+
+  const login = new nsLoginInfo("https://example.com", "https://autocomplete2", null,
+                                "singleuser", "singlepass", "uname", "pword");
+  Services.logins.addLogin(login);
+});
+</script>
+<p id="display"></p>
+
+<!-- we presumably can't hide the content for this test. -->
+<div id="content">
+  <!-- test single logins, with autocomplete=off set -->
+  <form id="form1" action="https://autocomplete2" onsubmit="return false;">
+    <input  type="text"       name="uname">
+    <input  type="password"   name="pword" autocomplete="off">
+    <button type="submit">Submit</button>
+  </form>
+
+  <form id="form2" action="https://autocomplete2" onsubmit="return false;">
+    <input  type="text"       name="uname" autocomplete="off">
+    <input  type="password"   name="pword">
+    <button type="submit">Submit</button>
+  </form>
+
+  <form id="form3" action="https://autocomplete2" onsubmit="return false;" autocomplete="off">
+    <input  type="text"       name="uname">
+    <input  type="password"   name="pword">
+    <button type="submit">Submit</button>
+  </form>
+
+  <form id="form4" action="https://autocomplete2" onsubmit="return false;">
+    <input  type="text"       name="uname" autocomplete="off">
+    <input  type="password"   name="pword" autocomplete="off">
+    <button type="submit">Submit</button>
+  </form>
+
+  <!-- control -->
+  <form id="form5" action="https://autocomplete2" onsubmit="return false;">
+    <input  type="text"       name="uname">
+    <input  type="password"   name="pword">
+    <button type="submit">Submit</button>
+  </form>
+
+<pre id="test">
+<script class="testbody" type="text/javascript">
+/** Test for Login Manager: multiple login autocomplete. **/
+let {ContentTaskUtils} = SpecialPowers.Cu.import("resource://testing-common/ContentTaskUtils.jsm", {});
+
+// Set the pref before the document loads.
+SpecialPowers.setBoolPref("signon.autofillForms.autocompleteOff", false);
+
+SimpleTest.registerCleanupFunction(() => {
+  SpecialPowers.clearUserPref("signon.autofillForms.autocompleteOff");
+});
+
+// Check for expected username/password in form.
+function checkFormValues(form, expectedUsername, expectedPassword) {
+  let uname = form.querySelector("[name='uname']");
+  let pword = form.querySelector("[name='pword']");
+  is(uname.value, expectedUsername, `Checking ${form.id} username is: ${expectedUsername}`);
+  is(pword.value, expectedPassword, `Checking ${form.id} password is: ${expectedPassword}`);
+}
+
+async function autoCompleteFieldsFromFirstMatch(form) {
+  // trigger autocomplete from the username field
+  await SimpleTest.promiseFocus(form.ownerGlobal);
+  let uname = form.querySelector("[name='uname']");
+  let shownPromise;
+  shownPromise = promiseACShown();
+  uname.focus();
+  await ContentTaskUtils.waitForCondition(() => {
+    return document.activeElement == uname;
+  }, "The textbox should have been focused");
+  await shownPromise;
+
+  let formFilled = promiseFormsProcessed();
+  await synthesizeKey("KEY_ArrowDown"); // open
+  await synthesizeKey("KEY_Enter");
+  await formFilled;
+  await Promise.resolve();
+}
+
+add_task(async function setup() {
+  listenForUnexpectedPopupShown();
+});
+
+/* Tests for autofill of single-user forms for when we honor autocomplete=off on password fields */
+add_task(async function test_form1_honor_password_autocomplete_off() {
+  await SimpleTest.promiseFocus(window);
+  // With the pref toggled off, and with autocomplete=off on the password field,
+  // we expect not to have autofilled this form
+  let form = document.getElementById("form1");
+  ok(form, "found form under test");
+  checkFormValues(form, "", "");
+
+  // ..but it should autocomplete just fine
+  await autoCompleteFieldsFromFirstMatch(form);
+  checkFormValues(form, "singleuser", "singlepass");
+});
+
+add_task(async function test_form2_honor_password_autocomplete_off() {
+  await SimpleTest.promiseFocus(window);
+  // With the pref toggled off, and with autocomplete=off on the username field,
+  // we expect to have autofilled this form
+  let form = document.getElementById("form2");
+  ok(form, "found form under test");
+  checkFormValues(form, "singleuser", "singlepass");
+});
+
+add_task(async function test_form3_honor_password_autocomplete_off() {
+  await SimpleTest.promiseFocus(window);
+  // With the pref toggled off, and with autocomplete=off on the form,
+  // we expect to have autofilled this form
+  let form = document.getElementById("form3");
+  ok(form, "found form under test");
+  checkFormValues(form, "singleuser", "singlepass");
+});
+
+add_task(async function test_form4_honor_password_autocomplete_off() {
+  await SimpleTest.promiseFocus(window);
+  // With the pref toggled off, and autocomplete=off on the username and password field,
+  // we expect not to have autofilled this form
+  let form = document.getElementById("form4");
+  ok(form, "found form under test");
+  checkFormValues(form, "", "");
+
+  // ..but it should autocomplete just fine
+  await autoCompleteFieldsFromFirstMatch(form);
+  checkFormValues(form, "singleuser", "singlepass");
+});
+
+add_task(async function test_form5() {
+  await SimpleTest.promiseFocus(window);
+  // (this is a control, w/o autocomplete=off, to ensure the login
+  // that was being suppressed would have been filled in otherwise)
+  let form = document.getElementById("form5");
+  ok(form, "found form under test");
+  checkFormValues(form, "singleuser", "singlepass");
+});
+</script>
+</pre>
+</body>
+</html>