| Íñigo Fernández de Velasco, 4th Duke of Frías | |
| Noble Family: | House of Velasco |
| Father: | Juan Sancho de Tovar, 1st Marquis of Berlanga |
| Mother: | María Girón, Lady of Gandul and Marchenilla |
| Spouse: | Ana Pérez de Guzmán y Aragón |
| Death Date: | 1585 |
Íñigo Fernández de Velasco, 4th Duke of Frías, Grandee of Spain, (in full, Spanish; Castilian: [[Don (honorific)|Don]] Íñigo Fernández de Velasco y Girón, cuarto duque de Frías, segundo marqués de Berlanga, sexto conde de Haro, segundo conde de Castilnovo, Condestable de Castilla, mayorazgo y señor de la Casa de Velasco, señor de la Casa y Estado de Tovar, Camarero mayor de Felipe II), ( - 1585), was a Spanish nobleman.
Fernández de Velasco was the son of Juan Sancho de Tovar, 1st Marquis of Berlanga and of María Girón, Lady of Gandul and Marchenilla. His original name was Íñigo de Tovar y Velasco, but he changed it and re-adopted his father's original last name when he inherited the Dukedom of Frías from his uncle Pedro Fernández de Velasco, who had no issue. He married Ana Pérez de Guzmán y Aragón, daughter of Juan Alfonso Pérez de Guzmán, 6th Duke of Medina Sidonia, with whom he had eleven children, among whom Juan Fernández de Velasco, 5th Duke of Frías.