A lubricating oil composition for transmissions comprises a lubricating base oil comprising (A) a lubricating base oil so adjusted to have a kinematic viscosity at 100° C. of from 1.5 to 5 mm2/s and a % CN of from 10 to 60 (B) a mineral lubricating base oil having a kinematic viscosity at 100° C. of from 10 to 50 mm2/s and a sulfur content of from 0.3 to 1 percent by mass and (C) a synthetic oil composed of carbon and hydrogen and having a number average molecular weight of from 2,000 to 20,000, in respective specific amounts and (D) an extreme pressure additive of from 0.05 to 2 percent by mass, based on the total amount of the composition, of comprising a phosphorus-based extreme pressure additive, a sulfur-based extreme pressure additive and/or a phosphorus-sulfur-based extreme pressure additive, wherein in the composition, the phosphorus content (P) is from 0.01 to 0.05 percent by mass, the total sulfur content (S) is from 0.05 to 0.3 percent by mass, and the P/S ratio is from 0.10 to 0.40. The lubricating oil composition has both excellent fuel economy performance and satisfactory durability for gears and bearings and furthermore excellent low temperature viscosity and oxidation stability.