Muhammad bin Nayef Al Saud, colloquially known by his initials MBN or MbN, is a former Saudi Arabian politician and businessman who served as the crown prince and first deputy prime minister of Saudi Arabia from 2015 to 2017 and as the minister of interior from 2012 to 2017.

The crown prince of Saudi Arabia is the second-most important position in Saudi Arabia, second to the King, and is his designated successor. Currently, the Crown Prince assumes power with the approval of the Allegiance Council after he is nominated by the King. This system was introduced to the country during the reign of King Abdullah. In the absence of the King, an order is issued to have the Crown Prince manage the affairs of the state until the King's return.