diff --git a/third_party/chrony/external.bzl b/third_party/chrony/external.bzl
new file mode 100644
index 0000000..e269c41
--- /dev/null
+++ b/third_party/chrony/external.bzl
@@ -0,0 +1,29 @@
+#  Copyright 2020 The Monogon Project Authors.
+#
+#  SPDX-License-Identifier: Apache-2.0
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+
+def chrony_external(name):
+    # ONCHANGE(//third_party/chrony:chrony.bzl): version needs to be kept in sync
+    version = "4.1"
+
+    http_archive(
+        name = name,
+        sha256 = "61a1b0879432695735a1e2a14e5d1ae499d3be15099c767501fbe695f46861da",
+        build_file = "@//third_party/chrony:chrony.bzl",
+        strip_prefix = "chrony-" + version,
+        urls = ["https://git.tuxfamily.org/chrony/chrony.git/snapshot/chrony-%s.tar.gz" % version],
+    )