Disclosed is a rear vehicle body structure of a vehicle, which comprises a rear floor panel, and a rear side frame joined to a lower surface of the rear floor panel to extend in a front-rear direction. A bottom wall of the rear side frame has a bottom reinforcing portion formed to protrude upwardly or downwardly, and a standing wall of the rear side frame located on a vehicle-widthwise inner side has a side reinforcing portion formed to protrude outwardly in the vehicle width direction. The bottom reinforcing portion includes a top, an outer inclined section extending from the top obliquely outwardly in the vehicle width direction, and an inner inclined section extending from the top obliquely inwardly in the vehicle width direction, wherein the inner inclined section has an inclination angle less than an inclination angle of the outer inclined section.