The Florida State League (FSL) was a Minor League Baseball league based in the state of Florida. It was one of three leagues classified as Class A-Advanced, the third-highest classification of minor leagues at the time. Each team that was in the league was affiliated with a Major League Baseball (MLB) team, and most played in their affiliate's spring training facility.

The league was founded in 1919 and continued almost uninterrupted until 2020. Initially, the FSL was classified as a Class D circuit. It was elevated to Class C from 1921 to 1924 before reverting to Class D from 1925 to 1928. The league went dormant from 1929 to 1935, but was revived as a Class D circuit from 1936 to 1941. After another period of inactivity from 1942 to 1945, it continued at Class D from 1946 to 1962. When the minor leagues were reconfigured in 1963, the FSL was reclassified as a Class A league. There it continued until the next reorganization in 1990 when it was elevated to Class A-Advanced. The league disbanded in 2021 and was replaced by the new Low-A Southeast league.