The Masmak Fort (), also called the Masmak Fortress or Masmak Palace, is a clay and mudbrick fort in ad-Dirah, Riyadh, Saudi Arabia. Built in 1865 for prince 'Abdurrahman ibn Sulaiman AlDabaan under the Emirate of Jabal Shammar, The fortress played an integral role in the Unification of Saudi Arabia, with the Battle of Riyadh, one of the most important conflicts of the Saudi unification, taking place in the fort. Since 1995, the fortress has been converted into a museum showcasing one of the most important landmarks of Saudi heritage.