Provided is a pneumatic tire in which a polygonal block group is provided between two circumferential main grooves in a tread ground contact width, the polygonal block group comprising a plurality of polygonal blocks with five or more sides which are demarcated by thin grooves and arranged in at least two longitudinal rows and a plurality of lateral rows, the longitudinal rows being arranged so that the polygonal blocks included in adjacent longitudinal rows differ in phase from each other in a tire circumferential direction; side block rows are provided, one on each of the two sides in the tire width direction of the polygonal block group, the side block rows comprising a plurality of side blocks which are demarcated by the circumferential main grooves, lateral grooves, and the thin grooves and arranged in the tire circumferential direction; and a length in the tire circumferential direction of a first side block included in a first side block row provided on one side is larger than the length in the tire circumferential direction of a second side block included in a second side block row provided on the other side.