diff --git a/gn.spec b/gn.spec
index aa515e5..01959be 100644
--- a/gn.spec
+++ b/gn.spec
@@ -128,7 +128,7 @@ AR='gcc-ar'; export AR
     --no-last-commit-position \
     --no-strip \
     --no-static-libstdc++
-ninja -C out -v
+ninja -j %{_smp_build_ncpus} -C out -v
 
 %if %{with html_docs}
 # There is a script, misc/help_as_html.py, that generates some HTML help, but