William D. Ryan (1861 – November 17, 1949) was an American labor unionist.
He became a breaker boy at a colliery, and joined the Knights of Labor, and then the United Mine Workers of America.
In 1897, he was elected as secretary-treasurer of his local, and became a full-time organizer for the union.
He then worked as an arbitrator for the Southwestern Interstate Coal Operators' Association, as a safety commissioner for the United States Bureau of Mines, and briefly ran a family coal and grain company.
[1] Ryan retired in 1935, and died in Kansas City, Missouri in 1949.