TBWA\Chiat\Day (/ˈtʃaɪ.æt/ CHY-at) is the American division of the advertising agency TBWA Worldwide. Created in the 1995 merger of TBWA and Chiat/Day, the agency operates offices in Los Angeles, New York City, Nashville, and Mexico City. Prior to the merger, Chiat/Day created internationally notable advertising, including "1984" for Apple Computer, the advertisement that introduced the Macintosh computer.^[1] The merger also inspired the creation of the ad agency St.Lukes by Chiat/Day's London office's employees.^[2]

TBWA Worldwide is part of the global marketing group Omnicom, with a reputation for more quirky or "disruptive" work. The youngest network in the group's portfolio, TBWA expanded rapidly in the final years of the 1990s and is a competitor to BBDO and DDB. A significant step came in 1998 when the agency absorbed Anglo-French marketing network GGT BDDP.

The current president of the Los Angeles office is Courtney Nelson; the New York office is headed by Rob Schwartz.^[3]

• "1984" (1983)
• "Lemmings" (1984)
• PowerBook 100 campaign with Kareem Abdul-Jabbar (1991)
• Dan & Dave (1992)
• "If only they'd used a Jiffi condom" (1993)
• Jack Box (1993)
• Crash Bandicoot (1996)^[4]
• Final Fantasy VII "$20 Million Campaign" (1997)
• "Think Different" campaign (1997)
• Taco Bell chihuahua (1997)
• Bloody Roar (1997)
• Bloody Roar II: The New Breed (1999)
• Gran Turismo 2 (1999)
• Pets.com sock puppet (1999)
• Hummingbird (television ad) Infiniti I35 (2001)^[5]
• Switch (2002)
• Absolut Vodka's "Absolut Marilyn" campaign (2005)
• Keep a Child Alive's "Spirit of a Child" campaign (2005)
• Hello Tomorrow (2005)
• "Get a Mac" campaign (2006)
• Gatorade "G" logo (2009)
• Southwest Airlines' "Welcome Aboard" campaign (2013)
• University of Phoenix (2019)

• Lee Clow
• Jay Chiat
• Guy Day

• Official website
• TBWA