diff --git a/zshrc b/zshrc
index 77b5270..96f223f 100644
--- a/zshrc
+++ b/zshrc
@@ -220,7 +220,11 @@ done
 __has_command vim && alias vi=vim
 __has_command gpg2 && alias gpg=gpg2
 
-__has_command nproc && export MAKEFLAGS="-j$(($(nproc) * 2))"
+if [ "$(uname -s)" = "Darwin" ]; then
+	export MAKEFLAGS="-j$(($(sysctl -n machdep.cpu.thread_count) * 2))"
+elif __has_command nproc; then
+	export MAKEFLAGS="-j$(($(nproc) * 2))"
+fi
 
 make() {
 	case "$PWD" in