diff --git a/meson.build b/meson.build
index 0fc0644..d66839c 100644
--- a/meson.build
+++ b/meson.build
@@ -106,6 +106,10 @@
     ],
 )
 
+if meson.is_subproject()
+    phosphor_dbus_interfaces_dep = phosphor_dbus_interfaces_dep.as_system()
+endif
+
 meson.override_dependency(
     'phosphor-dbus-interfaces',
     phosphor_dbus_interfaces_dep,