A ready-to-assemble (RTA) modular desktop cabinet has a multiple dowels, multiple clasp connectors, two side panels, a rear panel, a main shelf, a pedestal assembly and a top panel. The rear panel has a top board and a bottom board. The side panels are mounted parallelly and detachably mounted to the rear panel, the main shelf, the pedestal assembly and the top panel independently using dowels or clasp connectors. Further, the bottom board is hinged to the top board, so that the footprint of the folded rear panel is reduced for transport and storage. Furthermore, the RTA modular cabinet can be assembled and disassembled easily without needing tools.