William (Billy) Eisenberg (born September 5, 1937) is an American bridge and backgammon professional. In bridge, Eisenberg has won five Bermuda Bowl world team titles and he won the backgammon world title in 1975. Eisenberg is World Bridge Federation (WBF) and American Contract Bridge League (ACBL) Grand Life Master. He lived in Boca Raton, Florida, as of 1994 and 1998.
Eisenberg was from New York City in 1968, when the Dallas businessman Ira Corn hired him as an original member of the first full-time professional bridge team, the Dallas Aces. He left the team and moved from Texas to California in 1971.
- Bermuda Bowl (5) 1970, 1971, 1976, 1977, 1979
- North American Bridge Championships (14)
- United States Bridge Championships (7)
- Open Team Trials (5) 1969, 1974, 1975, 1977, 1979 (Jan)
- Senior Team Trials (2) 2005, 2008
- Other notable wins:
- Cap Gemini Pandata World Top Invitational Pairs (1) 1991
- Maccabiah Games (1) 1981
- Bermuda Bowl (1) 1975
- World Senior Teams (1) 1994
- North American Bridge Championships (15)
- United States Bridge Championships (3)
- Open Team Trials (1) 1973
- Open Pair Trials (1) 1968
- Senior Team Trials (1) 2001
- Other notable 2nd places:
- Cavendish Invitational Teams (1) 1985
- Cavendish Invitational Pairs (1) 1976
- Kent Goulding, Backgammon with the Champions (Kensington, MD: KG Publications), volume 1, 1981 ; volume 2, 1982 
Each volume covers Eisenberg in at least one match. "Series of annotated matches between good players. ... Commentary by Goulding, often in collaboration with Kit Woolsey." In particular, volume 1, number 1 was originally published as a booklet: "Paul Magriel vs. Billy Eisenberg: American Open Backgammon Championship, Las Vegas, Nevada, November 1979. Round 4, 15-point match (iv+42 pages)." 
- The 1st World Mind Sports Games. info.2008wmsg.chinaqiyuan.com
- Francis, Henry G., Editor-in-Chief; Truscott, Alan F., Executive Editor; Francis, Dorthy A., Editor, Fifth Edition (1994). The Official Encyclopedia of Bridge (5th ed.). Memphis, TN: American Contract Bridge League. p. 613. ISBN 0-943855-48-9. LCCN 96188639.
- "Eisenberg, William (Billy)". Hall of Fame. ACBL. Retrieved 2014-12-23.
- "Induction by Year". Hall of Fame. ACBL. Retrieved 2014-12-16.
- Citation at the ACBL Hall of Fame – with video interviews
- Billy Eisenberg international record at the World Bridge Federation.