Orachrysops warreni, the Warren's blue or Lost Valley Cupid, is a butterfly of the family Lycaenidae. It is found in South Africa and endemic to the Verloren Valei Nature Reserve in Mpumalanga, where it is only known from one hillside.
The species is named after R.T. Warren and his family, who discovered the butterfly while on surveys together in December 1988 and December 1989.
Its wingspan is 32âÂÂ36 mm for males and 32âÂÂ40 mm for females. Adults are on wing from December to January. There is one generation per year.
The larvae feed on Indigofera species.