Abstract: A heavy duty pneumatic tire comprises a tread portion provided with circumferentially continuously extending main grooves and axial grooves connecting between the main grooves to form blocks. The main grooves include a zigzag crown main groove disposed on each side of the tire equator, and a zigzag shoulder main groove disposed axially outside each crown main groove, wherein the groove width of the crown main groove is less than the groove width of the shoulder main groove. The axial grooves include crown axial grooves circumferentially dividing crown blocks disposed between the crown main grooves and each having a substantially hexagonal tread, and middle axial grooves circumferentially dividing middle blocks disposed between each crown main groove and the adjacent shoulder main groove and each having a substantially hexagonal tread, wherein the groove width of the middle axial grooves is more than the groove width of the crown axial grooves.