John Gast may refer to: John Gast (activist) (1772–1837), English shipwright and labour activist John Gast (baseball) (born 1989), American baseball pitcher John Gast (priest) (1715–1788) Archdeacon of Glendalough from 1764 to 1788 John Gast (painter) (1842–1896), Prussian-American painter and lithographer