Abstract: Modular closet systems and method. A modular closet system includes a plurality of stackable units. A modular closet system includes one stackable unit. Each unit includes a box having a first side panel, a second side panel, a top panel, a bottom panel, a back panel, a substantially hollow interior, and a front opening integral with the substantially hollow interior; and at least one external hanging rod having a proximal end and an opposing distal end. The proximal end is mounted to an exterior surface of a first stackable unit of the plurality of stackable units. The distal end is mounted to a support structure. The method includes providing a plurality of stackable units, arranging the stackable units, providing at least one hanging rod; attaching the first end of the hanging rod to an outer surface; and attaching the second end of the hanging rod to a first support structure.