The Cleveland Spiders were an American professional baseball team based in Cleveland, Ohio. The team competed at the major league level from 1887 to 1899, first for two seasons as a member of the now-defunct American Association (AA), followed by eleven seasons in the National League (NL). Early names for the team included the Forest Citys and Blues. The name Spiders itself emerged early in the team's inaugural NL season of 1889, owing to new black-and-gray uniforms and the skinny, long-limbed look of many players. National League Park served as the team's home for its first four seasons until the opening of League Park in 1891.

The National League of Professional Baseball Clubs, known simply as the National League (NL), is the older of two leagues constituting Major League Baseball (MLB) in the United States and Canada, and the world's oldest extant professional team sports league. Founded on February 2, 1876, to replace the National Association of Professional Base Ball Players (NAPBBP) of 1871–1875, the NL is sometimes called the Senior Circuit, in contrast to MLB's other league, the American League, which was founded 25 years later and is called the "Junior Circuit". Both leagues currently have 15 teams.