A pneumatic tire has paired bead portions, paired sidewall portions, a tread portion, a plurality of lug grooves extending from a shoulder area of the tread portion to reach a buttress area of the sidewall portion, and a block defined by the plurality of lug grooves. The block includes a shoulder block provided in the shoulder area, and a buttress block provided in the buttress area. The buttress area is provided with an annular rib annularly extending along a tire circumferential direction. The lug grooves are comparted into an outside lug groove positioned in an outer side of the annular rib, and an inside lug groove positioned in an inner side of the annular rib. A widened portion is provided in at least part of the plurality of lug grooves so as to enlarge a width of the annular rib.