Saudi Prince Talal bin Abdulaziz, a vocal supporter of reforms in the kingdom, has died aged 87, the royal court said on Saturday.
Prince Talal, the senior member of the al-Saud family and father of billionaire investor Alwaleed bin Talal, had been ill for several years.
He held various senior government positions in the 1950s and 60s, including communications minister and finance minister.
He lived in exile abroad in the 1960s, when Saudi authorities revoked his passport after he led a group of princes demanding constitutional reforms and allied himself with the then Egyptian President Gamal Abdel Nasser, the arch foe of the Saudi monarchy.
Prince Talal returned to the kingdom after Faisal bin Abdulaziz al-Saud became the king in 1964, and after toning down his rhetoric.
In 2011, he resigned from the Allegiance Council, the body responsible for overseeing the royal succession in the world's top oil exporter.
He also supported moves to give Saudi women greater rights to work and allow them to drive, and limit Riyadh's substantial military spending.
The royal court said funeral prayers would be offered for the prince in capital Riyadh on Sunday.
Prince Talal had been hospitalised in Riyadh. However, it was not clear where he died.