The Burger Wars is a series of off and on comparative advertising campaigns consisting of mutually-targeted advertisements that highlight the intense competition between hamburger fast food chains McDonald's, Burger King and others in the United States. The term first came into use during the late 1970s due to an attempt by Burger King to generate increased market and mind-share by attacking the size of bigger rival McDonald's hamburgers.
By the mid 1980s, the constant spending on advertising began to affect the major players. In 1987, Burger King laid off more than a hundred people from its corporate headquarters in Miami, Florida, while Dublin, Ohio-based Wendy's reported its first quarterly operating loss since its founding in 1969. Conversely, McDonald's operating revenue and profit increase while its market share also grew. Smaller chains, such as Hardee's, worked to keep from getting caught up in the extensive financial brinkmanship by avoiding the expensive ad campaigns and by staying in smaller, more geographically limited locations.
The New York Times states that the poor economy of the late 2010 recessionary period has led to the return of the Burger Wars. Because of tightened budgets, consumers have been forced to seek value and the major fast food chains are increasingly competing for those consumer dollars. The Wendy's chain has been at the forefront of the revival, airing a series of ads that feature founder Dave Thomas' daughter Melinda Lou Morse, the original "Wendy", advertising a series of new burgers and reviving its Where's the beef? advertising slogan. A March 2014 report in USA Today noted that Burger King is reviving the Burger Wars, including introducing clones of the Big Mac and McRib sandwiches, in response to business declines at McDonald's.
In a 2007 advertising campaign, Jack In the Box aired a series of television ads in the United States that disparaged several rivals' Angus-beef burgers in which it was alleged that they equated Angus beef with an anus. Rival chain operator CKE claimed the ads were misleading because they confuse consumers by comparing sirloin, a cut of meat found on all cattle, with Angus, which is a breed of cattle. CKE, operator of the Carl's Jr. and Hardees chains, had been noted for running ads that were controversial ads and claimed that there was no comparison between the ads they were running those of Jack In the Box because their ads did not insinuate their products came from an undesirable part of cows.
Because of their similar preparation styles and menus, the expansion of Five Guys into the territories of its Los Angeles-based counterpart In-N-Out has been described as newer version of the Burger Wars by several publications.
Breakfast Wars and Coffee Wars
The entry of Taco Bell into the breakfast fast-food business in 2014 for its United States locations triggered a related phenomenon known as the "Breakfast Wars", particularly between Taco Bell and McDonald's. Taco Bell rolled-out its breakfast menu by soliciting testimonials from people named Ronald McDonald, a move to which McDonald's responded by providing free coffee for a two-week period. Similarly, McDonald's Canada recently began offering free coffee for a week during Tim Hortons' "Roll Up the Rim to Win" campaign. Taco Bell's new value menu Dollar Cravings was instigated in reaction to McDonald's and Wendy's value menus.
Burger King's McWhopper proposal
On August 26, 2015, Burger King released an open letter to McDonald's proposing a joint promotion for Peace Day called the "McWhopper", a combination of the two restaurants' signature burgers.  The overture was rejected by McDonald's,  a response that drew mostly criticism for its tone and the sense of a missed opportunity. 
On September 1st, 2015, Burger King announced that they had been approached by representatives from Denny's, Wayback Burgers, Krystal & Giraffas about partnering on a similar project. Burger King then announced the "Peace Day Burger", which would feature ingredients from all five restaurants' burgers. 
- Cola Wars - similar type of competitive advertising programs between Coca-Cola and Pepsi.
- Fast food advertising
- "McDonald's Corporation". Funding Universe. Retrieved 15 January 2011.
A period of aggressive advertising campaigns and price slashing in the early 1980s became known as the "burger wars."
- Romeo, Peter (1988-12-19). "Brinker: a man with a vision". Nation's Restaurant News. Retrieved 2008-03-03.
- Arthur Lubow (1998-04-19). "Steal This Burger". The New York Times. Retrieved 2007-12-04.
Fast-food veterans surveying today's cutthroat competition will be reminded of the First Burger War
- Shriver Jr., Jube (6 May 1987). "Burger Wars Taking a Bite Out of Profit". Los Angeles Times. Retrieved 15 January 2011.
The nationwide burger wars, waged mostly in multimillion-dollar television commercials, are hitting some hamburger chains on the bottom line--forcing layoffs and losses.
- Hum, Scott (25 October 1993). "Hardee's: Back to Its Roots". Adweek. Retrieved 15 January 2011.
And it [Hardee's] kept its head down during the 'Burger Wars' of the early 1980s, when Burger King, McDonald's and Wendy's took on each other in expensive network TV battles.
- Elliot, Stuart (25 September 2011). "After 27 Years, an Answer to the Question, ‘Where’s the Beef?". New York Times. Retrieved 29 September 2011.
- Friedman, Nicky (March 19, 2014). Burger King hits McDonald's where it hurts. USA Today. Retrieved March 19, 2014.
- "Burger wars: Jack in the Box sued over ad". MSNBC. Associated Press. 29 May 2007. Retrieved 29 September 2011.
- Ta, Lien (6 May 2011). "Los Angeles Burger Wars: Five Guys Versus In-N-Out". Huffington Post. Retrieved 29 September 2011.
- "L.A. Burger Wars". National Association of Convenience Stores. 11 April 2011. Retrieved 29 September 2011.
- Horovitz, Bruce (March 29, 2014). Breakfast wars perk up: McDonald's pours free coffee. USA Today. Retrieved March 29, 2014.
- Moran, Andrew (March 2, 2011). "Coffee war: McDonald's free coffee v. Tim Hortons Roll Up the Rim". Digital Journal. Retrieved September 7, 2015.
- Brad Tuttle (18 August 2014). "Taco Bell Breathes New Life Into Fast-Food Dollar Menus - Money.com". Time (magazine). Retrieved 2014-08-25.
- Leslie Patton (15 August 2014). "Taco Bell to Introduce Dollar Menu Nationwide - Bloomberg". Bloomberg. Retrieved 2014-08-25.
- Ashley Lutz (15 August 2014). "Taco Bell Dollar Menu New - Business Insider". Business Insider. Retrieved 2014-08-25.