Olesya Yuryevna Velichko (Russian: ????? ??????? ???????; born May 20, 1981 in Taraz, Kazakhstan) is a modern pentathlete from Russia.
She is a multiple-time medalist at the World Championships, and a double champion at the 2001 Junior World Championships.
Velichko competed at the 2004 Summer Olympics in Athens, Greece, where she finished seventeenth in the women's event, with a score of 5,016 points.