The Province of Alessandria (Italian: Provincia di Alessandria) is an Italian province, with a population of some 430,000, which forms the southeastern part of the region of Piedmont. The provincial capital is the city of Alessandria.
With an area of 3,560 km² it is the third largest province of Piedmont after those of Cuneo and Turin. To the north it borders on the Province of Vercelli and to the west on the provinces of Turin and Asti. It shares its southern border with Liguria (provinces of Savona and Genoa). Its south-east corner touches the Province of Piacenza in Emilia Romagna, while to the east it borders on the Lombard Province of Pavia.