diff --git a/mkosi.finalize.chroot b/mkosi.finalize.chroot
index 36001af..c3dacd3 100755
--- a/mkosi.finalize.chroot
+++ b/mkosi.finalize.chroot
@@ -87,3 +87,6 @@ rm -rf /.cache
 
 ## Don't expose any X11 sessions; we're all-in on Wayland.
 rm -rf /usr/share/xsessions/
+
+## Replace Falkon with Firefox as the default browser, since that's what we pre-install.
+sed -i 's/org.kde.falkon.desktop/org.mozilla.firefox.desktop/' /usr/share/applications/kde-mimeapps.list