Megan Fletcher was born on 2 August 1989 in Reading, England. She was schooled at The Emmbrook School, in Wokingham, before going to the University of Bath, where she has trained since 2007 with Team Bath. As of 2014 she resides in Wokingham, which is where her club, Pinewood Judo Club, is located.

Fletcher began judo at the age of 5, and became a first dan black belt at the age of 15. In 2011, Fletcher participated for Great Britain at the World University Games in China.

At the 2014 Commonwealth Games, held in Glasgow, Scotland, Fletcher beat Moira de Villiers of New Zealand in the 70 kilograms judo final, by ippon with tate shiho gatame. Fletcher reached the final despite the fact that she had her face taped up after suffering an injury to her nose against the “gold medal hope” Sally Conway of Scotland in the semi-finals; Conway was the British judo number one going into the tournament. After her victory in the final, Fletcher dedicated it to her sensei, Don Werner, who had been her coach at Pinewood and died in January 2014 of cancer. Fletcher’s younger brother Ben Fletcher was due to compete in the judo 73 kilograms (161 lb) category, but a week before the event he suffered an injury and was forced to withdraw; he was replaced by Danny Williams. Megan is currently ranked 40th in the world in the 70kg category by the International Judo Federation.