The Sultan Ahmed Mosque (Turkish: Sultan Ahmet Camii) is a historic mosque in Istanbul.

The mosque is popularly known as the Blue Mosque for the blue tiles adorning the walls of its interior.

It was built from 1609 to 1616, during the rule of Ahmed I. Its Külliye contains a tomb of the founder, a madrasah and a hospice. While still used as a mosque, the Sultan Ahmed Mosque has also become a popular tourist attraction.