Infante Carlos, Count of Montemolín (31 January 1818 – 13 January 1861), was the Carlist claimant to the throne of Spain under the name Carlos VI after his father's renouncement in 1845, when he took the title of Conde de Montemolín (Count of Montemolín).

Carlos was born at the Royal Palace in Madrid, the elder son of Infante Don Carlos María Isidro and of his first wife, Infanta Maria Francisca of Portugal. The Second Carlist War (1847–49) took place during his reign.

On 10 July 1850, Carlos married his first cousin Princess Maria Carolina of Bourbon-Two Sicilies, fifth daughter of Francis I of the Two Sicilies and his second wife Maria Isabella of Spain. They would have no children.

In 1860, during a Carlist rising, he and his brother Infante Don Fernando were taken prisoners at San Carlos de la Rápita. They were later liberated.

In 1861, suddenly and unexpectedly, Carlos Luis, his wife Carolina and his brother Fernando died, probably from typhus. The three are buried in Trieste, in the chapel of Saint Charles Borromeo in the cathedral. He was succeeded in pretendence by his brother Juan, Count of Montizón.

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