diff --git a/pkgs/applications/editors/emacs/elisp-packages/elpa-packages.nix b/pkgs/applications/editors/emacs/elisp-packages/elpa-packages.nix
index 821960d1338e..59ad28052fae 100644
--- a/pkgs/applications/editors/emacs/elisp-packages/elpa-packages.nix
+++ b/pkgs/applications/editors/emacs/elisp-packages/elpa-packages.nix
@@ -87,7 +87,7 @@ self: let
         ];
 
         preInstall = ''
-          ./build.sh
+          ./build.sh -j$NIX_BUILD_CORES
         '';
 
         postInstall = ''