The royal palace announced the news on Saturday evening.
Princess Lalla was the widow of King Hassan II and the mother of reigning King Mohammed VI.
“As we mourn this painful loss, we ask the Almighty God to shower the deceased with his infinite mercy and grant her paradise, and to prolong the life of His Majesty King Mohammed VI, may God preserve him and perpetuate his glory,” the royal palace statement said.
Princess Lalla hailed from the prominent Amahzoune family, which is part of the Zayane tribe.
Her husband, King Hassan, who she wed in 1961, died in 1999.
She had five children: Princess Lalla Meryem, King Mohammed VI, Princess Lalla Asma, Princess Lalla Hasna, and Prince Moulay Rachid.