Infante Carlos of Spain (29 March 1788 – 10 March 1855) was an Infante of Spain and the second surviving son of King Charles IV of Spain and of his wife, Maria Luisa of Parma. As Carlos V, he was the first of the Carlist claimants to the throne of Spain. He is often referred to simply as 'Don Carlos'. He was a reactionary who was angry with liberalism in Spain and the assaults on the Catholic Church. He claimed the throne of Spain after the death of his older brother King Ferdinand VII in 1833. His claim was contested by liberal forces loyal to the dead king's infant daughter. The result was the bloody First Carlist War (1833–40). Don Carlos had support from Basque provinces and much of Catalonia, but it was not enough, and he lost the war and never became king. His heirs continued the arch-conservative cause, fought two more "Carlist" wars and were active into the mid-20th century, but never obtained the throne.

Carlos was born on 29 March 1788 at the Palacio Real de Aranjuez in Aranjuez, Community of Madrid. In 1808, Napoleon captured Madrid in the Battle of Somosierra, and he induced Carlos's father Charles IV and Carlos' older brother Ferdinand VII to renounce their rights to the throne of Spain. But Carlos, who was heir presumptive to his brother, refused to renounce his rights to the throne, which he considered to have been given to him by God. From 1808 until 1814, he and his brothers were prisoners of Napoleon at Valençay in France.

In 1814, Carlos and the rest of the Spanish royal family returned to Madrid. In September 1816, he married his niece Infanta Maria Francisca of Portugal (1800–1834), daughter of King John VI of Portugal and Carlos' sister Carlota Joaquina. Francisca was also sister of the second wife of Carlos' brother, Ferdinand VII. The couple had three sons:

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