Lafayette is a city in and the parish seat of Lafayette Parish, Louisiana, United States on the Vermilion River. The population was 110,257 at the 2000 census; a 2007 census estimate put the metropolitan area's population at 256,494.  It is the fourth largest city in the state. It is the larger principal city of the Lafayette-Acadiana, LA Combined Statistical Area, which, in 2007, had an estimated total population of 538,470.

The city was founded as Vermilionville in 1821 by a French-speaking Acadian named Jean Mouton. In 1884, it was renamed for General Lafayette, a French military hero who fought with and significantly aided the American Army during the American Revolutionary War.  The city's economy was primarily based on agriculture until the 1940s, when the petroleum and natural gas industry became dominant.

Lafayette has a strong tourism industry, attracted by the Cajun and Creole cultures of the surrounding region. Because of the Cajun culture's affinity for good food, it has one of the highest numbers of restaurants per capita of any U.S. city.

Lafayette is home to the Louisiana Ragin' Cajuns, the athletic teams of The University of Louisiana at Lafayette. It is also home to the Lafayette Bayou Bulls semi-pro football program which started in 2003. Between the years of 1995 and 2005, Lafayette was home to the Louisiana IceGators ECHL hockey team.

Lafayette is the home of the National Guard headquarters of the 256th Infantry Brigade, a military unit of over 3,000 soldiers that served in Iraq in the years of 2004-2005.

Lafayette is also home to the United States Marine Corps Reserve Unit, D. Co. AT Battalion. This unit has been on several deployments and currently have assets in Iraq.

Since the consolidation of city and parish governments, Lafayette has had a city-parish president as its chief executive, rather than a mayor as it had previously. The current Republican city-parish president is Joey Durel. As the largest city in the seventh congressional district of Louisiana, it overwhelmingly supported U.S. representative Charles Boustany in his races in 2004 and 2006; he is a citizen of Lafayette. In 2004, residents of Lafayette cast 57,000 ballots for George W. Bush and 31,000 for John F. Kerry. According to the Bay City Center for Voting Research, Lafayette is the ninth most conservative city in the nation and the fourth most conservative city in the South.

Lafayette serves as the retail and shopping hub of the Acadiana area, serving an eight parish area. The seat of this retail is the Mall of Acadiana. The mall features department stores Macy's, Dillards, JC Penney, and Sears. It also includes over 100 specialty stores, such as Express, Abercrombie & Fitch, American Eagle Outfitters, Talbots, Chico's, Nine West, and Coldwater Creek. Other retailers/stores that have recently located in Lafayette include Kohl's, Incredible Pizza Co., and Plato's Closet. Academy Sports and Outdoors recently built a new building for its Lafayette location to become one of the largest stores in the Academy chain.