A lubricant composition is described, particularly for engine oils, comprising a base oil of viscosity from 3 to 26 cSt (mm2/s) at 100° C. and an antiwear additive combination comprising (a) an oil soluble or oil dispersible phosphorus-free organo-molybdenum compound, (b) an ashless, sulfur-containing organo-phosphorus compound, and optionally (c) a zinc thiophosphate compound selected from one or more of zinc dialkyldithiophosphate, zinc diaiyldithiophosphate, zinc alkylaiyldithiophosphate and zinc arylalkyldithiophosphate. The molybdenum compound may be a carbamate, e.g., MoDTC but is preferably nitrogen-free, e.g., a carboxylate.