Friction modifier additives affect the frictional properties between two rubbing surfaces. They prevent scoring, reduce wear and noise, and can also help to prevent micropitting in industrial gear lubricants.

Friction modifiers are commonly used in gasoline engine oils, and are added to fluids for automatic and manual transmissions, tractor hydraulic systems, power steering, shock absorbers, and metalworking applications. In automatic transmission fluids and limited-slip axle lubricants, friction modifiers control torque application through clutch and band engagements.