A pneumatic tire is provided in the tread portion with circumferential grooves, main oblique grooves and auxiliary oblique grooves. The circumferential grooves include: a pair of axially outer grooves disposed one on each side of the tire equator; and at least one axially inner groove between the axially outer grooves, so as to divide the tread portion into at least four circumferential regions including: a pair of axially inner regions between the axially outer grooves and said at least one axially inner groove; and a pair of axially outer regions axially outside the axially outer grooves. The axially inner regions have an axial width L1 of from 0.15 to 0.25 times the critical tread width TW1. The main oblique groove extends across one of the axially inner regions so that the axially outer end is connected with the adjacent axially outer circumferential groove and the axially inner end is connected with the adjacent axially inner groove. The main oblique groove has an inclination angle .theta.1 of from 45 to 90 degrees at the axially outer end thereof, and an inclination angle .theta.2 at the axially inner end thereof which is less than the inclination angle .theta.1, when measured with respect to the tire circumferential direction. The auxiliary oblique grooves are arranged alternately with the main oblique grooves, and each extends from the adjacent axially outer circumferential groove to one of the axially adjacent main oblique grooves.