The Buick LaCrosse is a Buick automobile model introduced in the United States for the 2005 model year. It is a mid-size sedan and replaces the previous Buick Century and Buick Regal models. It uses an updated version of the 16-year old GM W platform, featuring V6 power and front wheel drive, rather than a planned stretched GM Epsilon platform.

Three trim lines are offered:

CX: Base model with the GM 3800 engine
CXL: Well-equipped, with the GM 3800 engine
CXS: Sportier model with the new GM High Feature engine
The new model, as is generally the case with Buick, stresses quality and reliability over styling or performance. Early press commentary noted somewhat unfavorably that the car looks very similar to Buicks of the past decade.

The name was reputedly chosen as a reference to the sport of lacrosse, seen as popular with a younger, more active demographic which Buick would like to pull into its showrooms. An introduction in the city of LaCrosse, Wisconsin was also planned.

In Canada, however, the car is called the Allure. News reports indicated that General Motors had to scrap the name LaCrosse for the Canadian market after discovering it was teenage slang for masturbation in French-speaking Quebec. Also, the Allure name is reportedly a tribute to another GM sedan, the now-discontinued Oldsmobile Intrigue; both "allure" and "intrigue" have basically the same meaning.

GM also sells a Buick with different styling and different engines in China, also called the LaCrosse. The engines for china are a 2.4L I4 and a 3.0L V6. Although the car is based on the American LaCrosse, it is a vastly differet, more modern car.