The women's marathon at the 2012 Olympic Games in London was held on the Olympic marathon street course on 5 August.

Edna Ngeringwony Kiplagat is a Kenyan professional long-distance runner. She was the 2011 and 2013 World Champion in the marathon. She established herself as an elite marathon runner with wins at the Los Angeles and New York City Marathons in 2010. Her personal best for the distance is 2:19:50 hours, set at the London Marathon in 2012. At age 37, Kiplagat won the 2017 Boston Marathon in a time of 2:21:52 hours, and won the marathon silver medal at the IAAF World Championships in London. At age 39, she was second at the 2019 Boston Marathon and fourth in the event at the following World Championships. At age 41, she won the 2021 Boston Marathon, becoming the oldest-ever winner of a World Marathon Major.