Pneumatic tire

A unidirectional pneumatic tire comprising a tread portion with a pair of inboard and outboard center main grooves (3A, 3B) and a pair of inboard and outboard shoulder main grooves (3C, 3D) to form a center portion, a pair of middle portions (4B, 4C), and a pair of shoulder portions (4D, 4E), each of the inboard center main groove, the outboard center main groove and the inboard shoulder main groove having a groove width of from 10 to 20 mm, the outboard shoulder main groove having a groove width of from 2 to 5 mm, the outboard shoulder portion provided with outboard shoulder lateral grooves (6E) each extending from the outboard tread edge without reaching the outboard shoulder main groove.