Anna Margaret Windsor (born May 17, 1976) is a retired Australian 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 m 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, Max Thomas Reidy, born 26 March 2006, and a daughter, Lucinda Summer Reidy, born 29 December 2008.