Nafissatou “Nafi” Thiam (born 19 August 1994) is a Belgian Walloon athlete who became Olympic champion in the heptathlon at the 2016 Summer Olympics and world champion in the same discipline at the 2017 World Championships. Born in Namur to a Belgian mother and a Senegalese father, Thiam is a member of RFCL, an athletics club from Liège, and is coached by Roger Lespagnard. She studies geography at the University of Liège.
Nafissatou Thiam started with athletics when she was seven years old. She won her first national age group titles in 2009, when she was already participating in the heptathlon. Her favourite athlete at the time was Swedish heptathlete Carolina Klüft.
On 3 February 2013, Thiam broke the junior indoor world record in the pentathlon at a meeting in Ghent with a total of 4558 points, breaking her personal best on 4 of the 5 events. Carolina Klüft, who later became Olympic champion and triple world champion, had held the record since 2002 with 4535 points. In doing so Thiam became the first Belgian woman athlete to break a world record. However, in March 2013, the record was not ratified due to a lack of anti-doping control on the day it was achieved. The testing took place the next day which was beyond the deadline.
On 18 July 2013 Thiam won the gold medal in the heptathlon at the European Junior Athletics Championships, achieving a new Belgian record score of 6298 points. On 13 August 2016, Thiam won the Heptathlon Gold Medal at the Olympic Games in Rio, achieving personal best marks in five of the seven disciplines and defeating reigning Olympic and World Champion Jessica Ennis-Hill. She was the Belgian flag bearer at the Olympic closing ceremony.
On May 28 2017, Thiam won the heptathlon at the Hypo-Meeting in Götzis, Austria with a total of 7013 points, making her the 4th woman to cross the symbolic 7000 points barrier. As of July 2017, she is number 3 on the all-time list behind Jackie Joyner-Kersee and Carolina Klüft.
On August 6 2017, Thiam won the heptathlon at the 2017 World Championships in London. In doing so, Thiam became the first Belgian to win a World Athletics Championships gold medal.