Kmart (sometimes styled as "K-Mart") is a chain of discount department stores in the United States, Puerto Rico, the U.S. Virgin Islands, and Guam. The chain acquired Sears in 2005, forming a new corporation under the name Sears Holdings Corporation. Kmart also exists in Australia and New Zealand (see Kmart Australia), although it now has no relation to the American stores except in name, after U.S. equity in the Australian business was purchased in the late 1970s. Kmart is the third largest discount store chain in the world, behind Wal-Mart and Target (Target Corporation); all three chains were founded in 1962.

As of January 30, 2010, Kmart operated a total of 1,327 (13 closing by late May) Kmart stores across 49 states, Guam, Puerto Rico, and the U.S. Virgin Islands. This store count included 1,361 discount stores, averaging convert92000sqftabbr=onlk=on, and 29 Super Centers, averaging convert165000sqftabbr=on.

Kmarts world headquarters were located in Troy, Michigan, in a sprawling complex which, since Kmarts relocation to Illinois, has been slated for demolition. However, at this current time, no actual demolition efforts are underway, and the proposed mixed-use complex the Pavilions of Troy, slated for the site has not begun construction due to issues with funding.

Kmart became known for its "Blue Light Specials". They occurred at surprise moments when a store worker would light up a mobile police light and offer a discount in a specific department of the store. At the height of Kmarts popularity, the phrase "attention Kmart shoppers" also entered into the American pop psyche, appearing in films and other media such as Troop Beverly Hills, Six Days Seven Nights, and Beetlejuice. According to MoviePlacement.com, the K Mart brand was also mentioned in 80s films such as Rain Man, Ruthless People, and Black Rain (Black Rain (American film)), but not in a positive light.