diff --git a/meson.build b/meson.build
index 88f37ba..bb01bcc 100644
--- a/meson.build
+++ b/meson.build
@@ -13,6 +13,7 @@ project(
 
 if get_option('headers_only')
     install_subdir('include/uapi', install_dir: get_option('includedir'))
+    install_subdir('include/sys', install_dir: get_option('includedir'))
     pkg = import('pkgconfig')
     pkg.generate(name: 'zinnia', description: 'Zinnia user API')
     subdir_done()