Pecos Bill is a mythical American cowboy.
Pecos Bill may also refer to:
- Pecos Bill (comics), an Italian comic series
- Pecos Bill (album), a 1988 album by Robin Williams
- Pecos Bill: The Greatest Cowboy of All Time, a 1937 novel by James Cloyd Bowman
- Pecos Bill, a segment of the 1948 animated feature Melody Time
- William Rufus Shafter (known by his nickname as "Pecos Bill"), a U.S. Army general