Sir William de Monte Alto of Ferne, also known as William de Mohaut (d.1327) was a 13th–14th century Scottish noble.
In 1296, William pledged homage to King Edward I of England at Inverness and his seal is appended to the Ragman Roll.
By 1305, William was given back the heritable position of Sheriff of Cromarty.
He appears to have sided with Robert de Brus in 1306 and was a signatory of the Declaration of Arbroath in 1320.
He died in 1327 during the Scottish siege of Norham Castle.