diff --git a/tools/check_for_upgrade.sh b/tools/check_for_upgrade.sh
index 5afd83c1e..c3b376d66 100644
--- a/tools/check_for_upgrade.sh
+++ b/tools/check_for_upgrade.sh
@@ -26,6 +26,9 @@ fi
 # oh-my-zsh directory.
 [[ -w "$ZSH" ]] || return 0
 
+# Cancel upgrade if no git command is available on this system.
+whence git >/dev/null || return 0
+
 if [ -f ~/.zsh-update ]
 then
   . ~/.zsh-update