diff --git a/.github/workflows/mkosi.yml b/.github/workflows/mkosi.yml
index 973eb4fd7fe..1e0b622f606 100644
--- a/.github/workflows/mkosi.yml
+++ b/.github/workflows/mkosi.yml
@@ -61,7 +61,7 @@ jobs:
           - distro: ubuntu
             release: noble
           - distro: fedora
-            release: "39"
+            release: "40"
           - distro: fedora
             release: rawhide
           - distro: opensuse
diff --git a/mkosi.conf.d/10-fedora.conf b/mkosi.conf.d/10-fedora.conf
index 006cdeded8d..4c3f76135ff 100644
--- a/mkosi.conf.d/10-fedora.conf
+++ b/mkosi.conf.d/10-fedora.conf
@@ -4,4 +4,4 @@
 Distribution=fedora
 
 [Distribution]
-@Release=39
+@Release=40
diff --git a/mkosi.conf.d/20-fedora-40.conf b/mkosi.conf.d/20-fedora-40.conf
new file mode 100644
index 00000000000..0b076ceb349
--- /dev/null
+++ b/mkosi.conf.d/20-fedora-40.conf
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
+[Match]
+Distribution=fedora
+Release=40
+
+[Distribution]
+Repositories=updates-testing
+Mirror=https://dl.fedoraproject.org/pub