Gordon Clapp (born September 24, 1948) is an American actor, known for playing the role of Detective Greg Medavoy for all 12 seasons on the television series NYPD Blue, winning an Emmy Award in 1998. He has appeared in numerous TV shows, movies (including 4 for his friend, director John Sayles), and stage plays.

In film, he appeared in Flags of Our Fathers as United States Marine Corps General Holland McTyeire "Howlin' Mad" Smith. He appeared in the Star Trek: Deep Space Nine episode "Vortex". On Broadway, he most recently appeared in the revival of David Mamet's Pulitzer Prize-winning play Glengarry Glen Ross, where he was nominated for a Tony Award for Best Performance by a Featured Actor in a Play.

Clapp, a distant relative of Ethan Allen, was born and raised in North Conway, New Hampshire. He attended South Kent School, a small private boarding school in Connecticut followed by Williams College, where he graduated as an English major. He is no relation to Gordon Clapp, former General Manager and Chairman of the Tennessee Valley Authority.

Gordon Clapp is best known as the Emmy-winning, Tony-nominated actor who charmed audiences as Det. Greg Medavoy on NYPD Blue and as loudmouth instigator Dave Moss in the 2005 Tony Award-winning Broadway revival of David Mamet's Glengarry Glen Ross. He will appear in the upcoming DreamWorks feature Flags of Our Fathers, directed by Clint Eastwood. Clapp plays gruff General Holland "Howlin' Mad" Smith, who helps mastermind the capture of the Japanese island of Iwo Jima during World War II. NYPD Blue finished its twelfth and final season in March, 2005, garnering Clapp a 1998 Emmy Award for Best Supporting Actor in a Drama Series. Glengarry's limited run went from the following May through August, earning Clapp a Tony Award nomination for Best Featured Actor. Clapp has maintained a vibrant career on both sides of the camera. Films include Moonlight Mile, Rules of Engagement and four films with director John Sayles - Sunshine State, Matewan, Eight Men Out and Return of the Secaucus Seven. TV appearances include Law & Order: SVU, Without A Trace, Deadwood, Less Than Perfect, American Family, Wings, Cheers and several TV movies. He also executive produced and starred in three short films: Trailer Talk and the award-winning Fast Cars & Babies and Bananas! Armed with a theater degree from prestigious Williams College, the New Hampshire native spent much of his early career in Canada, in regional and Toronto theater and as a company member of Ottawa's premiere National Arts Centre. His stage and TV work earned him nominations for a Dora Moore Award (Toronto's equivalent to the Tony) and Gemini Award (Canada's equivalent to the Emmy. American regional credits include the Philadelphia Drama Guild, Buffalo's Studio Arena and Boston's Huntington Theater. A talented writer, Clapp's work has appeared in the New York Post, LA Golf and Variety, which earned him a Los Angeles Press Club Award for his humorous account of winning an Emmy.