A post coupler is provided with a pair of coupler flanges having rivet receiving apertures for receiving rivets extending from horizontal shelf-supporting beams to facilitate vertical shelf placement in a shelving unit unfettered by the vertical disposition of the post couplers. Apertures in the coupler index with apertures in abutting corner post sections to permit rivet extension therethrough. The reverse bend flanges of the coupler have a length shorter than the overall length of the coupler and wrap around edges of post sections, to be coupled, from the inside to the outside.