Margaret Okayo (born 30 May 1976) is a professional Kenyan marathon runner.

Okayo's 2003 New York course record of 2:22:31 still stands today, despite the challenge of some of the world’s best distance runners having the benefit of improved shoe technology.

She was recruited by Kenya Prisons Service, home to the country's top women's marathon runners, in 1995 where she nurtured her running career.

Other marathons won by Okayo include Milan in 2003, San Diego in 2000 and 2001.

She represented her native Kenya in the 2004 Summer Olympic Games in Athens, Greece, but did not finish the marathon.