Konstanze "Koko" Klosterhalfen (born 18 February 1997)[2] is a German middle- and long-distance runner. She is the 2019 World Championship bronze medallist and 2022 European champion in the 5000 metres, becoming the first German medalist of the event at the World Athletics Championships and the first German winner of the event at the European Athletics Championships. At the European Indoor Championships, Klosterhalfen won silver medals for the 1500 metres in 2017 and the 3000 metres in 2019 and 2023. She took four individual medals at the European Cross Country Championships. In February 2020, she set a European indoor record in the 5000 m with 14:30.79, the fourth fastest time ever.
In 2017, Klosterhalfen became the youngest female athlete to run 800 m under 2 minutes, 1500 m under 4 minutes and 5000 m under 15 minutes. She is the current German record holder for 1500 m (indoor), one mile (out and indoor), 2000 metres, 3000 m (out and indoor), 5000 m (out and indoor) and 10,000 metres. She won multiple national titles.
In October 2022, on her debut at the distance, Klosterhalfen won the Valencia Half Marathon, setting the fastest female non-African mark in history and becoming the first non-African winner of the event since 2003 (by origin).[3][4]