England's Simon Middleton created history as the first coach of a women's team to win the prestigious award, having guided the Red Roses through a second successive calendar year unbeaten and 18 tests wins in a row, including back-to-back record wins over world champions New Zealand in November.
Middleton, in his seventh year as England head coach, saw his side score 57 tries and concede only 10 in 2021 as they added another Women's Six Nations title to their honours roll.
He beat out All Blacks coach Ian Foster, the duo of Allan Bunting and Cory Sweeney who coached the Black Ferns Sevens to Olympic gold and Wallabies coach Dave Rennie.
In other categories, including best players of the year will be named later this week.