Giorgio Massari (13 October 1687 – 20 December 1766) was an Italian late-Baroque architect from Venice.
Among his masterpieces are the Chiesa dei Gesuati (1726–43) located in Dorsoduro, Venice and the Palazzo Grassi-Stucky (1749).
In the latter, Massari executed a traditional elegant marble-fronted Grand Canal palace facade, with Baroque rhythms and variations to the arrangement of bays, disrupting the classical simplicity.
Massari also designed the scenographic staircase entry to Villa Giovanelli, Noventa Padovana.
Massari finished some works by Longhena, for example, the heavily decorated Ca' Rezzonico, also found on the Grand Canal.