The Remington Model 870 is a U.S.-made pump-action shotgun manufactured by Remington Arms Company, Inc. It is widely used by the public for sport shooting, hunting, and self-defense. It is also commonly used by law enforcement and military organizations worldwide.

The Remington 870 was the fourth major design in a series of Remington pump shotguns. John Pedersen designed the fragile Remington Model 10 (and later the improved Remington Model 29). Working with John Browning, Pedersen also helped design the Model 17 which was adopted by Ithaca as the Ithaca 37 and also served as the basis for the Remington 31. The Model 31 was well liked, but struggled for sales in the shadow of the Winchester Model 12. Remington sought to correct that in 1950 by introducing a modern, streamlined, rugged, reliable, and relatively inexpensive shotgun - the 870 Wingmaster.

Sales of the 870 have been steady. They reached 2 million guns by 1973 (ten times the number of Model 31 shotguns it replaced). By 1996, spurred by sales of the basic "Express" models, which were added as a lower cost alternative to the original Wingmaster line, sales topped seven million guns. On April 13, 2009 the ten millionth Model 870 was produced, and the 870 holds the record for best-selling shotgun in the history of the world.