Bou Ismaïl (Algerian Arabic: بو إسماعيل) is a city in Bou Ismaïl District, Tipasa Province, Algeria. In 2008 it had a population of 40,984. Its French colonial name was Castiglione.

Notable residents

• Jean-Pierre Bacri, French actor
• Boualem Khoukhi, Algerian-Qatari footballer