The 2021 Rachael Heyhoe Flint Trophy was the second edition of the Rachael Heyhoe Flint Trophy, an English women's cricket 50-over domestic competition, which took place between 29 May and 25 September 2021. It featured eight teams playing in a round-robin group, followed by a knock-out round. The holders were the Southern Vipers, who won the inaugural competition in 2020. It ran alongside the Charlotte Edwards Cup. The tournament was named after former England captain Rachael Heyhoe Flint, Baroness Heyhoe-Flint, who died in 2017.

The Rachael Heyhoe Flint Trophy is an English and Welsh women's cricket domestic competition, named after former England captain Rachael Heyhoe Flint, Baroness Heyhoe-Flint, who died in 2017. The first edition of the tournament took place during August and September 2020, with the Southern Vipers beating the Northern Diamonds in the final. Initially started as a one-off tournament, in February 2021 the England and Wales Cricket Board (ECB) announced it would return for the 2021 season as a permanent part of the women's domestic structure in England and Wales, alongside the Charlotte Edwards Cup.