Martino Longhi the Younger (March 18, 1602– December 15, 1660) was an Italian architect of the Baroque period active in Rome, in a milieu when the most prominent competition for commissions came from no less than Gian Lorenzo Bernini, Francesco Borromini, Carlo Rainaldi and Pietro da Cortona. Longhi had no children and he is buried in Viggiù, in Lombardy, where he died. Like some of his contemporary competitors, Longhi seems to have suffered from a lack of sociability.