Holly Madison Cullen (born December 23, 1979) is an American model and television personality, best known for appearing as Hugh Hefner's number one girlfriend with Bridget Marquardt and Kendra Wilkinson on the reality TV series The Girls Next Door. Although not a Playboy Playmate, she has appeared in nude pictorials with her Girls Next Door costars and fellow Hefner girlfriends Bridget Marquardt and Kendra Wilkinson. Her most recent work was as a contestant on the eighth season of Dancing with the Stars.

Holly was born Holly Madison Cullen in Astoria, Oregon. Her father traveled around due to work in the timber industry, and from ages two through eleven, she grew up on Prince of Wales Island, Alaska, near Ketchikan. Her family then moved back home to St. Helens, Oregon. She attended Portland State University for two years as a double-major in theatre and psychology.

In 1999, Madison moved to Los Angeles to attend Loyola Marymount University. To afford college tuition, she competed to become a Hawaiian Tropic model and worked at Hooters. After being noticed, she began to receive invitations to the Playboy Mansion. After more than a year of visiting the mansion, Madison was invited to move in. She became one of Hefner's seven official girlfriends in August 2001. In February 2002, after all but two of his girlfriends left, Madison became Hef's "#1 Girl" and moved into his bedroom at the mansion. She was named among the top Hooters girls of all time in 2008 as part of the restaurant's twenty-fifth anniversary.