William Lyall

William Lyall may refer to:
 * William Lyall (politician), Australian politician, member of the Victorian Legislative Assembly
 * William Lyall (priest), English churchman
 * William Lyall (businessman) Scottish–American merchant and businessman
 * William John Campbell Lyall, Scottish rugby union player
 * Bill Lyall, Canadian politician, member of the Northwest Territories Legislative Assembly
 * Billy Lyall, Scottish musician