Jay Dee Penn (born December 13, 1978), is an American mixed martial artsist and Brazilian Jiu-Jitsu practitioner of Anglo-Irish and Korean descent who is currently the Ultimate Fighting Championship (UFC) Lightweight Champion. In 2000, he became the first American-born winner of the World Jiu-Jitsu Championship in the black-belt category.[3]

Penn is a former UFC Welterweight Champion and was a coach on the The Ultimate Fighter 5 reality show. He became only the second fighter to win UFC titles in two different weight classes (the other being Randy Couture), after he won the lightweight title at UFC 80, having previously won the UFC’s welterweight title from Matt Hughes at UFC 46. He is currently ranked by  as the #1 Lightweight fighter in the world.

Win 15–5–1 Diego Sanchez TKO (Doctor Stoppage) UFC 107: Penn vs. Sanchez 2009-12-12 5 2:37
Win 14–5–1 Kenny Florian Submission (Rear Naked Choke) UFC 101: Declaration 2009-08-08 4 3:45
Loss 13–5–1 Georges St-Pierre TKO (Corner Stoppage) UFC 94: St-Pierre vs. Penn 2 2009-01-31 4 5:00
Win 13–4–1 Sean Sherk TKO (Knee and Punches) UFC 84: Ill Will 2008-05-24 3 5:00
Win 12–4–1 Joe Stevenson Submission (Rear Naked Choke) UFC 80: Rapid Fire 2008-01-19 2 4:02
Win 11–4–1 Jens Pulver Submission (Rear Naked Choke) The Ultimate Fighter 5 Finale 2007-06-23 2 3:12
Loss 10–4–1 Matt Hughes TKO (Punches) UFC 63: Hughes vs. Penn 2006-09-23 3 3:53
Loss 10–3–1 Georges St-Pierre Decision (Split) UFC 58: US vs. Canada 2006-03-04 3 5:00
Win 10–2–1 Renzo Gracie Decision (Unanimous) K-1 World Grand Prix 2005 in Hawaii 2005-07-29 3 5:00
Loss 9–2–1 Lyoto Machida Decision (Unanimous) K-1 Hero’s 1 2005-03-26 3 5:00
Win 9–1–1 Rodrigo Gracie Decision (Unanimous) Rumble on the Rock 6 2004-11-20 3 5:00
Win 8–1–1 Duane Ludwig Submission (Arm Triangle Choke) K-1 MMA ROMANEX 2004-05-22 1 1:45
Win 7–1–1 Matt Hughes Submission (Rear Naked Choke) UFC 46: Supernatural 2004-01-31 1 4:39
Win 6–1–1 Takanori Gomi Submission (Rear Naked Choke) Rumble on the Rock 4 2003-10-10 3 2:35
Draw 5–1–1 Caol Uno Draw UFC 41: Onslaught 2003-02-28 5 5:00
Win 5–1 Matt Serra Decision (Unanimous) UFC 39: The Warriors Return 2002-09-27 3 5:00
Win 4–1 Paul Creighton TKO (Strikes) UFC 37: High Impact 2002-05-10 2 3:23
Loss 3–1 Jens Pulver Decision (Majority) UFC 35: Throwdown 2002-01-11 5 5:00
Win 3–0 Caol Uno KO (Punches) UFC 34: High Voltage 2001-11-02 1 0:11
Win 2–0 Din Thomas TKO (Strikes) UFC 32: Showdown in the Meadowlands 2001-06-29 1 2:42
Win 1–0 Joey Gilbert TKO (Strikes) UFC 31: Locked and Loaded 2001-05-04 1 4:57