A pneumatic tire includes a tread portion provided with shoulder blocks in a row along each tread edge. The shoulder blocks are provided in a row divided by a circumferential groove and first shoulder grooves and second shoulder grooves. The first and second shoulder grooves alternate in the tire circumferential direction and each extend from the circumferential groove to the tread edge. A circumferential width (WLo) of the first shoulder groove at the tread edge is larger than a circumferential width (WSo) of the second shoulder groove at the tread edge. The ratio (WLo/WSo) of the circumferential width (WLo) to the circumferential width (WSo) is larger than a ratio (WLi/WSi) of a circumferential width (WLi) of the first shoulder groove to a circumferential width (SWi) of the second shoulder groove, each measured at the circumferential groove.