The Hassan II Mosque (Arabic: مسجد الحسن الثاني‎) is a religious building in Casablanca, Morocco. It is the largest mosque in the country and the 7th largest mosque in the world. Its minaret is the world's tallest at 210 m (689 ft).

It stands on a promontory looking out to the Atlantic. A total of 105,000 worshippers can gather for prayer at the mosque simultaneously, 25,000 inside the mosque and another 80,000 on the mosque's ground outside.

The building was designed by the French architect Michel Pinseau and built by Bouygues.