Robert Thin was born in Edinburgh, the youngest surviving son of James Thin, founder of James Thin, Booksellers. He was educated at the Royal High School and the University of Edinburgh, graduating MA in 1883 and MB CM in 1887. After graduation he served as House Surgeon to Professor John Chiene and House Physician to Dr John Wylie at the Royal Infirmary of Edinburgh, followed by a residency at the Royal Hospital for Sick Children, Edinburgh.
