William Warner (January 28, 1812 – July 1868) was a Michigan politician.
Warner initially studied for the ministry, but abandoned this pursuit due to health considerations.
Warner was connected with the Vermont Central Railroad until 1855, when he arrived in Detroit.
On November 6, 1866, Warner represented the same district again from January 2, 1866 to December 31, 1867.
At the time of his death, he was the president of Detroit Bridge and Iron Works.