diff --git a/public/src/client/register.js b/public/src/client/register.js
index 0a98b324fa..26096c29e1 100644
--- a/public/src/client/register.js
+++ b/public/src/client/register.js
@@ -159,14 +159,18 @@ define('forum/register', [
 		} else if (!utils.isUserNameValid(username) || !slugify(username)) {
 			showError(username_notify, '[[error:invalid-username]]');
 		} else {
-			api.head(`/users/bySlug/${username}`, {})
-				.then(() => {
-					showError(username_notify, '[[error:username-taken]]');
-				})
-				.catch(() => {
+			Promise.allSettled([
+				api.head(`/users/bySlug/${username}`, {}),
+				api.head(`/groups/${username}`, {}),
+			]).then((results) => {
+				if (results.every(obj => obj.status === 'rejected')) {
 					showSuccess(username_notify, successIcon);
-				})
-				.finally(callback);
+				} else {
+					showError(username_notify, '[[error:username-taken]]');
+				}
+
+				callback();
+			});
 		}
 	}
 
diff --git a/public/src/modules/api.js b/public/src/modules/api.js
index 207342d1c1..5438d3167f 100644
--- a/public/src/modules/api.js
+++ b/public/src/modules/api.js
@@ -42,7 +42,7 @@ define('api', () => {
 		});
 	}
 
-	api.get = (route, payload = {}, onSuccess) => call({
+	api.get = (route, payload, onSuccess) => call({
 		url: route + (Object.keys(payload).length ? ('?' + $.param(payload)) : ''),
 	}, onSuccess);
 
diff --git a/src/controllers/write/groups.js b/src/controllers/write/groups.js
index d0e711aaa5..243d5b0cf7 100644
--- a/src/controllers/write/groups.js
+++ b/src/controllers/write/groups.js
@@ -6,6 +6,10 @@ const helpers = require('../helpers');
 
 const Groups = module.exports;
 
+Groups.exists = async (req, res) => {
+	helpers.formatApiResponse(200, res);
+};
+
 Groups.create = async (req, res) => {
 	const groupObj = await api.groups.create(req, req.body);
 	helpers.formatApiResponse(200, res, groupObj);
diff --git a/src/routes/write/groups.js b/src/routes/write/groups.js
index 36c0a669f2..1f78447170 100644
--- a/src/routes/write/groups.js
+++ b/src/routes/write/groups.js
@@ -10,6 +10,7 @@ const setupApiRoute = routeHelpers.setupApiRoute;
 module.exports = function () {
 	const middlewares = [middleware.authenticate];
 
+	setupApiRoute(router, 'head', '/:slug', [middleware.assert.group], controllers.write.groups.exists);
 	setupApiRoute(router, 'post', '/', [...middlewares, middleware.checkRequired.bind(null, ['name'])], controllers.write.groups.create);
 	setupApiRoute(router, 'delete', '/:slug', [...middlewares, middleware.assert.group], controllers.write.groups.delete);
 	setupApiRoute(router, 'put', '/:slug/membership/:uid', [...middlewares, middleware.assert.group], controllers.write.groups.join);
diff --git a/src/socket.io/user.js b/src/socket.io/user.js
index 292fb1ea48..cc39126d8a 100644
--- a/src/socket.io/user.js
+++ b/src/socket.io/user.js
@@ -30,7 +30,7 @@ require('./user/ban')(SocketUser);
 require('./user/registration')(SocketUser);
 
 SocketUser.exists = async function (socket, data) {
-	sockets.warnDeprecated(socket, 'HEAD /api/v3/users/bySlug/:userslug');
+	sockets.warnDeprecated(socket, 'HEAD /api/v3/users/bySlug/:userslug *AND* HEAD /api/v3/groups/:slug');
 
 	if (!data || !data.username) {
 		throw new Error('[[error:invalid-data]]');