diff --git a/sys/dev/evdev/evdev.c b/sys/dev/evdev/evdev.c
--- a/sys/dev/evdev/evdev.c
+++ b/sys/dev/evdev/evdev.c
@@ -215,7 +215,7 @@
 	ev_sysctl_tree = SYSCTL_ADD_NODE_WITH_LABEL(&evdev->ev_sysctl_ctx,
 	    SYSCTL_STATIC_CHILDREN(_kern_evdev_input), OID_AUTO,
 	    ev_unit_str, CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, "",
-	    "device index");
+	    "device_index");
 
 	SYSCTL_ADD_STRING(&evdev->ev_sysctl_ctx,
 	    SYSCTL_CHILDREN(ev_sysctl_tree), OID_AUTO, "name", CTLFLAG_RD,