William Gillis may refer to:
Willie Gillis, Norman Rockwell's fictional character Willie Gillis, a television character in The Rookies Bill Gillis (1936–2009), Canadian politician William Gillis (businessman) (1788–1869), American businessman, real estate developer and pioneer William Gillis (politician) (1859–1929), British Member of Parliament for Penistone
See also William Gillies (disambiguation)