William Jex (23 March 1885 - 19 February 1934) was an English footballer who played as an inside left with Norwich City, Doncaster Rovers, Rotherham Town and Croydon Common, and in the Football League with Gainsborough Trinity in the early 20th century.
He was Doncaster's top scorer in each of the three seasons he played for them.
Jex was born in Thorpe Hamlet, a suburb of Norwich, and by trade he was a painter and decorator.
He is said to have developed a weak heart after catching a fever following a swim in the River Wensum in Norwich.