diff --git a/git-gui/lib/commit.tcl b/git-gui/lib/commit.tcl
index 60edf99752..e3183a658e 100644
--- a/git-gui/lib/commit.tcl
+++ b/git-gui/lib/commit.tcl
@@ -388,6 +388,9 @@ A rescan will be automatically started now.
 	# -- Create the commit.
 	#
 	set cmd [list commit-tree $tree_id]
+	if {[is_config_true commit.gpgsign]} {
+		lappend cmd -S
+	}
 	foreach p [concat $PARENT $MERGE_HEAD] {
 		lappend cmd -p $p
 	}