A lubricating oil composition used in an internal combustion engine contains lubricating base oil; a disulfide compound as a component (A), a no-boron-containing ashless dispersant as a component (B), and a boron-containing ashless dispersant as a component (C). The disulfide compound as the component (A) is represented by the following formula (1) and/or the following formula (2). The no-boron-containing ashless dispersant as the component (B) has in its side chain: an alkyl group having a number average molecular weight of 500 to 3,000; or an alkenyl group having a number average molecular weight of 500 to 3,000. The boron-containing ashless dispersant as the component (C) has in its side chain: an alkyl group having a number average molecular weight of 500 to 4,000; or an alkenyl group having a number average molecular weight of 500 to 4,000. R1OOC-A1-S—S-A2-COOR2  (1) R7OOC—CR9R10—CR11(COOR8)—S—S—CR16(COOR13)—CR14R15—COOR12  (2)