A pneumatic tire comprises a tread portion provided along each tread edge with shoulder blocks defined by a circumferentially extending shoulder main groove and shoulder lateral grooves extending from the shoulder main groove to the tread edge. The shoulder main groove is made up of groove segments curved convexly toward the tire equator so that each groove segment comprises a first inclined part and a second inclined part. The shoulder lateral grooves extend at 45 to 90 degrees with respect to the tire circumferential direction, and are coupled with the first inclined parts of the groove segments. The shoulder blocks are each subdivided by a shoulder sub groove extending at an angle of from 15 to 45 degrees with respect to the tire circumferential direction. The shoulder sub groove has an axially outer end connected with the shoulder lateral groove and an axially inner end coupled with the second inclined part.