Fadrique Enríquez de Mendoza (1390 – 23 December 1473) was the second Admiral of Castile, Count of Melgar and Rueda, and second Lord of Medina del Rioseco.

When his father died in 1429, Alonso Fadrique inherited his estate and titles, including ricohombre, Master of Order of Santiago, lord of Medina de Rioseco, Castro Verde and Torrelobatón.

According to his contemporary Hernando del Pulgar (1436–1492), he was small in stature, a little nearsighted, and he gained much honor and fame with his performance as commander of the fleet of Castile.

[1] Fadrique played an important role at court as one of the main advisers of King John II of Castile.

In 1432, he fought alongside Pedro Manrique de Lara against the princes Henry and Peter near Cáceres, Alburquerque and Acagala.

During this short period of peace, Henry married Blanche II of Navarre, and Fadrique was godfather of the couple.