An adjustable rack assembly for a washing appliance. The adjustable rack assembly includes a rack having a first side wall and an opposing second side wall, a first rail assembly having a first plurality of horizontal rails, and a second rail assembly having a second plurality of horizontal rails. A first support assembly is coupled to the first side wall of the rack and includes a first support plate configured to be removably coupled to the first rail assembly at a first horizontal rail of the first plurality of horizontal rails. A second support assembly is coupled to the second side wall of the rack and includes a second support plate configured to be removably coupled to the second rail assembly at a first horizontal rail of the second plurality of horizontal rails.