A dishwasher has an interior with a tub and a dish rack slidably attached to the tub. The dish rack has vertically-oriented side rail and a height adjustment system. The adjustment system includes height adjustment mechanisms alongside the walls of the dish rack for vertically shifting the dish rack between lowered and raised positions relative to the tub. Each of the adjustment mechanisms includes an adjuster arm fixed vertically relative to the tub, with a locking boss at the first end, and a locking clip on the adjuster arm having at least one locking tab adapted to couple with the locking boss to prevent the rack from shifting vertically relative to the adjuster arm. The locking clip has a pair of interference ribs engaging a pair of side rails to prevent rotational movement of the rack with respect to the dishwasher.