Cholesteryl oleyl carbonate (COC) is an organic chemical, a carbonate ester of cholesterol and oleyl alcohol with carbonic acid.

It is a liquid crystal material forming cholesteric liquid crystals with helical structure.

It is a transparent liquid, or a soft crystalline material with melting point around 20 °C.

It can be used with cholesteryl nonanoate and cholesteryl benzoate in some thermochromic liquid crystals.

It is used in some hair colors,[1] make-ups, and some other cosmetic preparations.