Stackable hat storage unit has frame defining a rectangular opening and comprising top, bottom, left and right side panels, parallel horizontal strings that traverse the opening attached to the left and right side panels, the strings spaced so that a folded cap on the string conceals a portion of a similarly folded cap on an adjacent string, the top panel including a vertical notch to receive a hanger-type hook for mounting the frame onto a crossbar and two vertical wall notches to receive screws projecting from a wall, the top panel of the frame curving forward and projecting downwardly to form a top panel lip covering part of the top panel's height, a top portion of the top panel having an upside down "U" cross-section, the top panel lip fitting over a top edge of the bottom panel of a second frame to form a plurality of frames that function together.