The Buick Rainier is a mid-size luxury SUV that was manufactured by General Motors and marketed by Buick for the 2004 to 2007 model years. It was named after Mount Rainier, and — along with the Saab 9-7X — served as the replacement for the Oldsmobile Bravada.

Buick is a division of the American automobile manufacturer General Motors (GM). Started by automotive pioneer David Dunbar Buick in 1899, it was among the first American automobile brands and was the company that established General Motors in 1908. Before the establishment of General Motors, GM founder William C. Durant had served as Buick's general manager and major investor. With the demise of Oldsmobile in 2004, Buick became the oldest surviving American carmaker.