To provide a pneumatic tire by which uneven wear resistance can be increased and the formation of cracks and/or fractures in the ribs can be effectively prevented. This pneumatic tire comprises a tread portion, sidewall portions, and bead portions, wherein the tread portion includes five main grooves extending in the tire circumferential direction that partition six rows of ribs, a plurality of first sipes is formed in each edge portion of center ribs, intermediate ribs, and shoulder ribs, a plurality of first narrow grooves is formed in each of the center ribs and the intermediate ribs so as to form a connection between the main grooves, a plurality of second narrow grooves is formed in each of the center ribs and the intermediate ribs so as to connect the first narrow grooves, an interval Pg 1 of the first narrow groove is from 20 mm to 60 mm, an interval Ps 1 of the first sipe is from 15% to 45% of the interval Pg 1 of the first narrow groove, a ratio Wa/TDW of a width Wa of the center ribs to a tread portion development width TDW is from 0.08 to 0.18, a ratio Wb/TDW of a width Wb of the intermediate ribs to the tread portion development width TDW is from 0.08 to 0.18, and a ratio Wc/Wa of a width Wc of the shoulder ribs to the width Wa of the center ribs is from 1.20 to 1.30.