To provide a lubricating oil composition for automatic transmission which ensures both a high torque capacity of a wet clutch and a good .mu.(coefficient of friction)-V (sliding velocity) characteristic in an automatic transmission along with excellent storage stability in a high humidity environment. A lubricating oil composition for automatic transmission is provided, which comprises a lubricating base oil made of a mineral oil and/or a synthetic oil formulated with a friction modifier, a metal detergent and an ashless dispersant, characterized in that said ashless dispersant consists of an succinimide having boron at a rate of three or less atoms in one molecule of the ashless dispersant.