To provide a lubricating oil composition for automatic transmissions that can achieve both fuel-saving property and the durability of parts while retaining the initial viscosity.

The lubricating oil composition for automatic transmissions comprises (A) a base oil having a kinematic viscosity of 9-20 mm2/s at 40C and, incorporated therewith, (B) 0.5-30 mass% of a polymethacrylate-based viscosity index improver having a weight-average molecular weight (in terms of polystyrene) of 15,000-70,000 and (C) 0.5-30 mass% of a polymethacrylate-based viscosity index improver having a weight-average molecular weight of 100,000-500,000, wherein (D) the content ratio of the component (B) to the component (C) is 3-10 by mass; (E) the kinematic viscosity of the composition is 5.2-6.5 mm2/s at 100C; and (F) the composition has a viscosity index of at least 180.