What was the first name of Alan Turing's mother?

Alan Turing's mother's first name was Ethel. Her full name was Ethel Sara Turing, née Stoney, and she was born into an Anglo-Irish family connected with British India.

Ethel married Julius Mathison Turing in Dublin in 1907. Julius served in the Indian Civil Service, while Ethel was the daughter of Edward Waller Stoney, chief engineer of the Madras Railways. The family therefore had strong links to both Ireland and colonial India.

Alan was born in London in 1912 while Julius was on leave from his posting in India. Ethel and Julius wanted their children raised in Britain, although their professional and family lives continued to involve travel between Britain and India. A common mix-up is to give “Sara” as the answer: Sara was Ethel's middle name, not her first name. Ethel is the canonical first-name answer.