A lubricating oil composition for internal combustion engines which comprises a major amount of an oil of lubricating viscosity and a minor amount of an additive composition comprising an overbased metal-containing detergent composition and a molybdenum-containing friction modifier; wherein the overbased metal-containing detergent composition comprises 0.01 to 0.4 wt.%, in terms of calcium content, based on the total amount of the lubricating oil composition, of a calcium salicylate having an alkyl group having an average carbon atom number in the range of 14 to 18, at least 60 mol.% of said alkyl group having a carbon atom number in the range of 14 to 18, wherein the calcium salicylate is a mixture of a plurality of calcium salicylates; and 0.01 to 0.4 wt.%, in terms of calcium content, based on the total amount of the lubricating oil composition, of at least one of the following calcium-containing detergent: calcium sulfonate having an alkyl group having an average carbon atom number in the range of 20 to 24, at least 60 mol.% of said alkyl group having a carbon atom number in the range of 20 to 24, wherein the calcium sulfonate is a mixture of a plurality of calcium sulfonates; and calcium salicylate having an alkyl group having an average carbon atom number in the range of 20 to 28, at least 60 mol.% of said alkyl group having a carbon atom number in the range of 20 to 28, wherein the calcium salicylate is a mixture of a plurality of calcium salicylates. wherein the overbased metal-containing detergent composition comprises 0.01 to 0.4 wt.%, in terms of calcium content, based on the total amount of the lubricating oil composition, of a calcium salicylate having an alkyl group having an average carbon atom number in the range of 14 to 18, at least 60 mol.% of said alkyl group having a carbon atom number in the range of 14 to 18, wherein the calcium salicylate is a mixture of a plurality of calcium salicylates; and 0.01 to 0.4 wt.%, in terms of calcium content, based on the total amount of the lubricating oil composition, of at least one of the following calcium-containing detergent: calcium sulfonate having an alkyl group having an average carbon atom number in the range of 20 to 24, at least 60 mol.% of said alkyl group having a carbon atom number in the range of 20 to 24, wherein the calcium sulfonate is a mixture of a plurality of calcium sulfonates; and calcium salicylate having an alkyl group having an average carbon atom number in the range of 20 to 28, at least 60 mol.% of said alkyl group having a carbon atom number in the range of 20 to 28, wherein the calcium salicylate is a mixture of a plurality of calcium salicylates. calcium sulfonate having an alkyl group having an average carbon atom number in the range of 20 to 24, at least 60 mol.% of said alkyl group having a carbon atom number in the range of 20 to 24, wherein the calcium sulfonate is a mixture of a plurality of calcium sulfonates; and calcium salicylate having an alkyl group having an average carbon atom number in the range of 20 to 28, at least 60 mol.% of said alkyl group having a carbon atom number in the range of 20 to 28, wherein the calcium salicylate is a mixture of a plurality of calcium salicylates.