Alonso Álvarez de Toledo y Urquijo, 12th Marquess of Valdueza, GE (born 30 September 1939) is a Spanish nobleman.

[1] He is the current president of the Junta de Homologación and formerly of the Spanish delegation of the International Council for Game and Wildlife Conservation, an organ he was also vice-president of.

Franco improvised a boarding school in "Las Jarillas", a hunting finca north of Madrid belonging to Alonso's uncle, the 4th Marquess of Urquijo.

He included 8 children of some of the most aristocratic families of Spain, with the aim of educating the young prince in the traditional upper-class Spanish way.

He married Isabel Argüelles y Salaverría, daughter of Jaime Argüelles y Armada, grand cross of the Order of Charles III and of Margarita Salaverría y Galarraga, dame of the Order of Isabella the Catholic, 8 June 1963 at San Fermín de los Navarros in Madrid.