Motor oil, engine oil, or engine lubricant is any one of various substances used for the lubrication of internal combustion engines. They typically consist of base oils enhanced with various additives, particularly antiwear additives, detergents, dispersants, and, for multi-grade oils, viscosity index improvers. The main function of motor oil is to reduce friction and wear on moving parts and to clean the engine from sludge and varnish (detergents). It also neutralizes acids that originate from fuel and from oxidation of the lubricant (detergents), improves the sealing of piston rings, and cools the engine by carrying heat away from moving parts.

Valvoline Inc. is an American retail automotive services company, publicly traded on the NYSE as VVV. It licenses the name for a number of Valvoline-labeled automotive oil, additives, and lubricants. It also owns the Valvoline Instant Oil Change, Great Canadian Oil Change and Valvoline Express Care car repair chains. As of 2023, it is the second largest oil change service provider in the United States with 10% market share and over 1,650 locations.