Antonio Longo (14 April 1742- 26 May 1820) was an Italian painter and priest in a late Baroque style.
His initial training was with a local painter of Val di Fiemme, Giuseppe Alberti.
In Rome, he served as chaplain in the Convitto dell'Anima, and in part through Cristoforo Unterberger, who was Prince of the Accademia di San Luca, was able to befriend Anton Raphael Mengs and Pompeo Battoni.
In 1798, when Rome was occupied by Napoleonic armies, Longo as an Austrian citizen was forced to return to Varena, where he continued to paint.
He painted sacred subjects for churches in Val di Fiemme and Val di Fassa, Aldeno, Agordo, Pergine Valsugana, Madrano (a frazione within Pergine Valsugana), Riva del Garda, Salorno, Egna, Mezzolombardo, Mezzocorona, Margreid an der Weinstraße, Montalbiano (a frazione within Valfloriana), and Baselga di Pinè.