Salah Bey ben Mostefa (; born 1725 in Izmir, died 1792 in Constantine), was the bey of the Beylik of Constantine in the Deylik of Algiers from 1771 to 1792, and one of the most famous in the province. Salah Bey's governance is marked by a victorious participation against the Invasion of Algiers (1775) during the Spanish-Algerian war (1775-1785) and his works of urban planning in Constantine.