W. H. Seward Thomson (December 16, 1856 – November 29, 1932) was a United States federal judge.
Born in Beaver County, Pennsylvania, Thomson attended Washington and Jefferson College, and Marshall College in Huntington, West Virginia before reading law to enter the bar in 1880. He was in private practice in Beaver, Pennsylvania from 1881 to 1894, and then in Pittsburgh, Pennsylvania until 1914.
On July 7, 1914, Thomson was nominated by President Woodrow Wilson to a seat on the United States District Court for the Western District of Pennsylvania vacated by James S. Young. Thomson was confirmed by the United States Senate on July 21, 1914, and received his commission the same day. He assumed senior status on February 21, 1928, serving in that capacity until his death, in 1932.