Meseret Defar Tola (Amharic: መሰረት ደፋር; born 19 November 1983) is an Ethiopian long-distance runner who competes chiefly in the 3000 metres and 5000 metres events. She has won medals at top-tier international competitions including Olympic and World Championship gold medals over 5000 metres. She broke the world record in the event in 2006, broke it again in 2007 and held it until 2008, when fellow Ethiopian Tirunesh Dibaba beat her time.
Defar has been successful in the 5000 m at the Olympic Games, taking gold at the 2012 London Olympics, 2004 Athens Olympics and bronze at the 2008 Beijing Olympics. She has experienced similar success in the World Championships, taking silver in 2005 Helsinki Championships and gold at the 2007 Osaka Championships.
Defar held the indoor records for the 5000 metres, 3000 metres and two-mile run. She has dominated the 3000 m indoor event, winning four consecutive gold medals at the IAAF World Indoor Championships from 2004 to 2010. She is also a two-time champion at the All-Africa Games, a four-time medalist at the African Championships and a two-time gold medalist at the World Junior Championships.