Marilyn Chinwenwa Okoro (born 23 September 1984 in London) is an athlete of Igbo ancestry. She received a bronze medal for the 800 metres at both the 2007 and 2008 IAAF World Athletics Final. She was on the bronze winning 4 × 400 m relay at the 2007 World Championships in Athletics. She represented Great Britain for Athletics at the 2008 Summer Olympics - Women's 800 metres and finished 6th (Time: 1:59.53) in the semi-finals.
On June 26, 2007 Okoro graduated from the University of Bath with a B.A. degree in politics and French, then starting her first season as a fulltime athlete. She speaks four languages (English, French, Spanish and Igbo) and sings in the jazz band The Felonius Monks.