Anna Margaret Windsor (born 17 May 1976) is an Australian former competitive swimmer who won four medals in freestyle relays at the world championships in 1993, 1995 and 1998. She also competed at the 1996 and 2000 Summer Olympics and finished sixth in the 4×100-metre freestyle relay in 1996.
She was born in Sydney, but her family moved to Orange, New South Wales, when she was eight months old. After the 2000 Olympics, she retired from swimming to focus on studies. She received a university degree in medicine in 2004.
She is married to Ben Reidy; they have a son born in 2006, and a daughter born in 2008.