The 2021 Herculis was the 35th edition of the annual outdoor track and field meeting in Monaco.

Held on 9 July at Stade Louis II, it was the sixth leg of the 2021 Diamond League – the highest level international track and field circuit.

On the women's side, the meeting was highlighted by Faith Kipyegon running 3:51.07 to beat Sifan Hassan and scare the world record.

Upon learning of his mistake, Kigen slowed to a jog, allowing Lamecha Girma to pass and win the race.

[2] Athletes competing in the Diamond League disciplines earned extra compensation and points which went towards qualifying the Diamond League finals in Zürich.