KBR, Inc. (formerly Kellogg Brown & Root) NYSE: KBR is an American engineering, construction and private military contracting company, formerly a subsidiary of Halliburton, headquartered in Houston. The company also has large offices in Arlington, Birmingham, Newark, Delaware and Leatherhead, UK. After Halliburton acquired Dresser Industries in 1998, Dresser's engineering subsidiary, The M. W. Kellogg Co., was merged with Halliburton's construction subsidiary, Brown & Root, to form Kellogg Brown & Root. KBR and its predecessors have received many contracts with the United States military including during World War II, the Vietnam War, and Operation Iraqi Freedom.

KBR is the largest non-union construction company in the United States. The company's corporate offices are in the KBR Tower in Downtown Houston.

In 1901, Morris Kellogg founded The M. W. Kellogg Company in New York City. The company was incorporated in 1905 and its headquarters was moved to Jersey City, New Jersey. Initially Kellogg’s main business was power plant construction and fabrication of power plant components, but the development of hammer forge welding techniques helped ready the company to move into refining as the petroleum industry developed. Kellogg was announced the number one construction company for years 1993 to 1995. This is mainly due to their work in the Dulles Greenway.