Sir William Carter (25 May 1848 – 14 October 1932) was an English insurance executive who was elected Mayor of Windsor, Berkshire, thirteen times. Carter was born in Marlow, Buckinghamshire, and became a painter and decorator and later a gardener. He then joined the Prudential Assurance Company as a clerk and served successively at their offices in Marlow, Maidenhead and Windsor, becoming superintendent of the Windsor office in 1879 and remaining there until his retirement in 1908.