diff --git a/git-gui/git-gui.sh b/git-gui/git-gui.sh
index 3e5907a4609b15..64bd3ac1f6f435 100755
--- a/git-gui/git-gui.sh
+++ b/git-gui/git-gui.sh
@@ -101,6 +101,9 @@ proc _which {what args} {
 
 	if {[is_Windows] && [lsearch -exact $args -script] >= 0} {
 		set suffix {}
+	} elseif {[string match *$_search_exe $what]} {
+		# The search string already has the file extension
+		set suffix {}
 	} else {
 		set suffix $_search_exe
 	}