diff --git a/netwerk/cookie/CookieService.cpp b/netwerk/cookie/CookieService.cpp
index 26512fc254b7..83125110dc24 100644
--- a/netwerk/cookie/CookieService.cpp
+++ b/netwerk/cookie/CookieService.cpp
@@ -1699,12 +1699,6 @@ bool CookieService::CheckDomain(CookieStruct& aCookieData, nsIURI* aHostURI,
   nsAutoCString hostFromURI;
   aHostURI->GetAsciiHost(hostFromURI);
 
-  // IPv6 fixup
-  if (hostFromURI.Contains(':')) {
-    hostFromURI.Insert("[", 0);
-    hostFromURI.Append(']');
-  }
-
   // if a domain is given, check the host has permission
   if (!aCookieData.host().IsEmpty()) {
     // Tolerate leading '.' characters, but not if it's otherwise an empty host.
diff --git a/netwerk/test/unit/test_cookie_ipv6.js b/netwerk/test/unit/test_cookie_ipv6.js
deleted file mode 100644
index 90234e1be44c..000000000000
--- a/netwerk/test/unit/test_cookie_ipv6.js
+++ /dev/null
@@ -1,52 +0,0 @@
-/* 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/. */
-
-/*
- *  Test that channels with different LoadInfo
- *  are stored in separate namespaces ("cookie jars")
- */
-
-"use strict";
-
-let ip = "[::1]";
-XPCOMUtils.defineLazyGetter(this, "URL", function() {
-  return `http://${ip}:${httpserver.identity.primaryPort}/`;
-});
-
-const { HttpServer } = ChromeUtils.import("resource://testing-common/httpd.js");
-
-let httpserver = new HttpServer();
-
-function cookieSetHandler(metadata, response) {
-  response.setStatusLine(metadata.httpVersion, 200, "Ok");
-  response.setHeader(
-    "Set-Cookie",
-    `Set-Cookie: T1=T2; path=/; SameSite=Lax; domain=${ip}; httponly`,
-    false
-  );
-  response.setHeader("Content-Type", "text/html");
-  response.setHeader("Content-Length", "2");
-  response.bodyOutputStream.write("Ok", "Ok".length);
-}
-
-add_task(async function test_cookie_ipv6() {
-  Services.prefs.setIntPref("network.cookie.cookieBehavior", 0);
-  Services.prefs.setBoolPref(
-    "network.cookieJarSettings.unblocked_for_testing",
-    true
-  );
-
-  httpserver.registerPathHandler("/", cookieSetHandler);
-  httpserver._start(-1, ip);
-
-  var chan = NetUtil.newChannel({
-    uri: URL,
-    loadUsingSystemPrincipal: true,
-  });
-  let req = await new Promise(resolve => {
-    chan.asyncOpen(new ChannelListener(resolve));
-  });
-  var cm = Cc["@mozilla.org/cookiemanager;1"].getService(Ci.nsICookieManager);
-  equal(cm.cookies.length, 1);
-});
diff --git a/netwerk/test/unit/xpcshell.ini b/netwerk/test/unit/xpcshell.ini
index a9ff7063ca1a..62cdef7ac8c8 100644
--- a/netwerk/test/unit/xpcshell.ini
+++ b/netwerk/test/unit/xpcshell.ini
@@ -462,4 +462,3 @@ skip-if = os == "android"
 skip-if = os == "android"
 [test_httpssvc_priority.js]
 skip-if = os == "android"
-[test_cookie_ipv6.js]