Carlism is a traditionalist and legitimist political movement in Spain seeking the establishment of a separate line of the Bourbon dynasty on the Spanish throne. This line descended from Don Carlos, Count of Molina (1788–1855), and was founded due to dispute over the succession laws and widespread dissatisfaction with the Alfonsine line of the House of Bourbon. The movement was at its strongest in the 1830s but had a revival following Spain's defeat in the Spanish-American War in 1898, when Spain lost its last remaining significant overseas territories of Cuba, Guam, the Philippines, and Puerto Rico to the United States.
An exceptionally long-lived movement, Carlism was a significant force in Spanish politics from 1833 until the end of the Francoist regime in 1975. In this capacity, it was the cause of several major wars during the 19th century, and an important factor in the Spanish Civil War in the 1930s.