Simon Gregory Kukes (Russian: Семен Григорьевич Кукес; born 5 December 1946) is a Russian-born American chemist and retired oil industry businessman. He immigrated to the US to work in the oil industry in the late 1970s, and returned to Russia with AMOCO in 1995. He became vice president at YUKOS, president of TNK-BP from 1998 until 2003, and returned to head Yukos, replacing Mikhail Khodorkovsky. Officially retired he is still consulting in the oil businesses.