HRH Infante Don Juan of Spain, Count of Barcelona, Juan Carlos Teresa Silvestre Alfonso de Borbón (June 20, 1913 - April 1, 1993), was the fourth son and designated heir of King Alfonso XIII of Spain, the monarch replaced by the Second Spanish Republic, and father of King Juan Carlos, under whom a constitutional monarchy would be restored.

On October 12, 1935, in Rome, he married Maria Mercedes Borbón y Orleans (also known as Doña María de las Mercedes de Borbón y Orleans or as HRH Princess Maria de las Mercedes Cristina Genara Isabel Luisa Carolina Victoria of Bourbon Two-Sicilies).

They had four children:

1. HRH Infanta Doña Maria del Pilar Alfonsa Juana Victoria Luisa Ignacia de Todos los Santos of Spain, Duchess of Badajoz (born 1936)
2. HM Juan Carlos, King of Spain (born 1938)
3. HRH Infanta Doña Margarita Maria de la Victoria Esperanza Jacoba Felicidad Perpetua de Todos Los Santos of Spain, Duchess of Soria, 2nd Duchess of Hernani (born 1939)
4. HRH Infante Don Alfonso of Spain (1941 - 1956)

After living in Rome, he moved his residence to Estoril, Portugal.

He was fond of the sea, and had tattoos of a marine theme from his time in the British Royal Navy.

To assert his claim to the throne, he used the title of Count of Barcelona, a sovereign title associated with the Spanish crown.

When General Francisco Franco changed the form of government in Spain to a monarchy, he characterised it as a reinstitution. However, fearing that Don Juan would be too liberal and roll back the Falangist state, Franco passed over Don Juan, who would have been king if the monarchy had continued uninterrupted, in favour of his son, Juan Carlos, who Franco believed would be more likely to continue the Francoist state after his death. Juan Carlos surprised many by his support of democratising Spain.

The Count of Barcelona renounced his claim to the throne in 1977, forty-six years after Spain had been declared a republic, eight years after being deposed by Franco and two years after his son had become King Juan Carlos. In return, his son officially granted him the title of Count of Barcelona, which he had claimed for so long.

He is buried at the Royal Crypt of the monastery of San Lorenzo del Escorial, near Madrid.