Abstract: A moisture-wicking cover that encircles the adjusting strap of an adjustable hat to wick moisture, such as sweat, away from the wearer of the hat. The cover is an elongate sleeve having an exterior surface formed from a moisture-wicking material. The adjusting strap is positioned in an inner lumen of the sleeve. A stitched ribbon formed in the sewing process is positioned in the inner lumen and acts as a lock to prevent the cover from rotating relative to the hat during use.