William Seymour
William Seymour may refer to:
- William Seymour (MP for Herefordshire), MP for Herefordshire (UK Parliament constituency)
- William Digby Seymour (1805–1872), MP for Kingston-upon-Hull
- William Digby Seymour, QC, lawyer and poet, MP for Sunderland and Somerset
- William H. Seymour, American politician
- William J. Seymour, American Pentecostal minister
- William Kean Seymour, British writer
- William Seymour Jr., American banker who twice served as president of the New York Stock Exchange
- William Seymour (Congressman), US representative from New York from 1835 to 1837
- William Seymour (British Army officer, born 1664), lieutenant-general, MP for Cockermouth, Totnes and Newport
- William Seymour, 2nd Duke of Somerset
- William Seymour, 3rd Duke of Somerset
- William Seymour Tyler, American historian
- William Henry Seymour, British Army officer
- Lord William Seymour (British Army officer), senior British Army officer