The lubricating oil composition of the invention includes a lubricating base oil with a kinematic viscosity at 100° C. of 1-6 mm2/s, a % Cp of 70 or greater and a % CA of no greater than 2, and a viscosity index improver which, when added to the lubricating base oil, results in an A/B ratio of less than 3.2 and a C/B ratio of less than 1.5. A is the thickening effect on the kinematic viscosity at 100° C., B is the thickening effect on the HTHS viscosity at 150° C., and C is the thickening effect on the HTHS viscosity at 100° C.