Juan de Vega y Enríquez, 1st Count of Grajal, 6th Lord of Grajal, Viceroy of Navarre (1542), Viceroy and Captain General of Sicily (1547–1557), presidente del Consejo de Castilla, was an ambassador of Charles V, Holy Roman Emperor.

He first served as ambassador of Charles V at Rome, where he met Ignatius of Loyola.

[1] After the Order of Saint John refused to take control of Mehdia in Tunisia, Charles V ordered de Vega to capture the city to deter the Muslim piracy.

[2] The enterprise known as the Capture of Mahdia (1550) was successful, spearheaded on the sea by a Spanish naval expedition under the command of the Genoese condottiero and admiral Andrea Doria and the Spaniard Bernardino de Mendoza.

After two years, the army of De Vega burnt Mehdia, but retaliated against the Order for not accepting the city, and prohibited exportation of wheat to the island of Malta, which was ruled by the Order.