Porta Sant'Alessandro, City gate in Città Alta, Bergamo, Italy

Porta Sant'Alessandro is the western gate of Bergamo's Upper Town, part of the Venetian walls. It is more rustic than the similar Porta Sant'Agostino: the outer face is grey stone up to the cordon line, the upper part yellow up to the roof. In 1958 the tympanum received a Vicenza stone lion of Saint Mark by sculptor Antonio Milani, on a design by Luigi Angelini.

The gate belongs to the Venetian walls built from 1561, when the Basilica of Sant'Alessandro outside the gate was demolished; a document from 892 already records that basilica, the city's first cathedral and the original resting place of the saint's tomb. The relic was moved to the former Basilica of San Vincenzo in 1600, which became the Cathedral of Sant'Alessandro, while the empty tomb was transferred to the Church of Sant'Alessandro della Croce. Since 9 July 2017 the walls are part of the UNESCO serial site of Venetian defensive works.

The gate is named after the church of Sant'Alessandro, demolished in 1561 to build the Venetian walls. A document of 892 calls it the great basilica outside the gate, the first church dedicated to Bergamo's patron saint and the first episcopal cathedral, holding his tomb. At its demolition the relic was moved in 1600 to the former basilica of San Vincenzo, now Bergamo Cathedral.

Porta Sant'Alessandro faces west, not north: it is reached from the historic centre by climbing through the Upper Town towards the western edge. The outer face is grey stone up to the cordon, the upper part yellow up to the roof, so the gate is easy to recognise from outside the walls.

The gate was the most heavily protected by the gun emplacements of the Sant'Alessandro bastion, and although structurally similar to Porta Sant'Agostino it is far more rustic. In 1958, to a design by Luigi Angelini, the tympanum received a lion of Saint Mark in Vicenza stone, carved by the Vicenza sculptor Antonio Milani.