Reebok International Limited is an American (formerly British) footwear and apparel company, and a subsidiary of German sporting goods giant Adidas since 2005. Reebok produces and distributes fitness, running and CrossFit sportswear including clothing and footwear. It is the official footwear and apparel sponsor for Ultimate Fighting Championship (UFC), CrossFit, and Spartan Race.

In 1958, Reebok was established as a companion company to J.W. Foster and Sons, founded in 1895 in Bolton, Lancashire, England. From 1958 until 1986, all Reebok apparel featured the U.K. flag., to signify the company's British origins. The Union Flag is featured on Reebok's "Classic" line of apparel.

The company's global headquarters are located in Boston, Massachusetts, U.S., with regional offices in Amsterdam, Montreal, Hong Kong, and Mexico City.

In November 2016, Reebok announced they would be moving their headquarters from the Boston suburb of Canton to the innovation and design building in the seaport district of South Boston. The reasons for the move, according to the company, were to be located in an urban environment that is more desirable to millennial workers and to “clarify the roles” of United States offices. The move was completed in autumn of 2018.