John J. Flanagan (born May 7, 1961) is an American politician from Long Island, New York. A Republican, Flanagan represented New York's 2nd State Senate district from 2003 to 2020. He also served as senate majority leader from 2015 to 2019, and as senate minority leader from 2019 to 2020. Prior to his senate tenure, Flanagan served in the New York State Assembly from 1987 to 2002.