Polyalpha-olefins (PAO or roly-alpha-olefin) are the oil base (base oil) used to produce lubricants. Group IV base oils are hydrogenated oligomers of olefins produced by catalytic polymerization of linear alpha-olefins.

PAOs have several advantages: excellent low-temperature properties, high viscosity index, low vaporizability. They do not contain unsaturated and polycyclic aromatic hydrocarbons, sulfur compounds, nitrogen and other impurities, which determines high thermo-oxidative stability. The susceptibility of PAO to antioxidants and their anti-seize/anti-wear synergism is higher than that of mineral oils.