Dennis John Gearin (October 15, 1897 – March 11, 1959) was a former Major League Baseball pitcher. He spent most of his career (1915, 1918-1931) in the minors, playing mostly for the Milwaukee Brewers of the American Association. He played two seasons with the New York Giants (1923–1924) and Boston Braves (1924).
In his only appearance for the Braves, he gave up five earned runs on three hits and two walks without recording an out in a 14-8 loss to the Brooklyn Robins, thus giving him an infinite ERA with the team.