Lisa Sauermann (born September 25, 1992) is a German schoolgirl who became the most successful participant in the International Mathematical Olympiad. She is ranked No.1 in the International Mathematical Olympiad Hall of Fame, having won four gold medals (2008–2011) and one silver medal (2007) at this event.

In all of those occasions she represented Germany. She was the only student to achieve a perfect score at IMO 2011.

Sauermann attended Martin-Andersen-Nexö-Gymnasium Dresden when she was in 12th grade. She won the Franz Ludwig Gehe Prize in 2011 and the gold medal in the age group III, the 11th–12th grade competition. As a result she won a trip to the Royal Academy of Sciences in Stockholm. To achieve this, she presented a new mathematical theorem with a proof in an outstanding work entitled “Forests with Hypergraphs”.

She is currently studying at the University of Bonn.