Elinor Catherine Hamlin ("née" Nicholson; 24 January 1924 – 18 March 2020) was an Australian obstetrician and gynaecologist. With her New Zealand husband Reginald Hamlin, she co-founded the Addis Ababa Fistula Hospital in Addis Ababa, Ethiopia. As of 2020, it is world's only medical centre giving free obstetric fistula repair surgery to poor women suffering from childbirth injuries. Hamlin has been called a pioneer of her field by the United Nations agency UNFPA.