ThePrince orPrincess of Viana (Spanish:Príncipe de Viana,Basque:Vianako Printzea) is one of the titles of the heir of theCrown of Spain. Other associated titles originate from the rest of the kingdoms that formed Spain:Prince of Asturias,Prince of Girona,Duke of Montblanc,Count of Cervera andLord of Balaguer.

Originally it was the title of the heir of theKingdom of Navarre. It was instituted byCharles III for his grandsonCharles, born of the marriage between his daughterBlanche I of Navarre andJohn II of Aragon. The title was used also forGaston, the son and heir ofEleanor of Navarre andGaston IV of Foix. Its creation and use was a reflection of a Western European trend of bestowing upon the heirs of a kingdom rents for his personal benefit. In pre-unification Spain, the comparable titles were Prince of Asturias, inCastile and Prince of Girona, inAragon. In other European states, similar titles includedDauphin, in France,Prince of Beira orPrince of Brazil, in Portugal andPrince of Wales, in England.

Due to several historical events, such as the 15th century dynastic union of Spain betweenIsabella I of Castile andFerdinand II of Aragon, as well as the early 16th centuryinvasion and annexation of Navarre byFerdinand II of Aragon, the title lost its importance. This was exacerbated when the Kingdom of Navarre ended up divided between theKingdom of France and theKingdom of Spain. While the title "Prince of Viana" has recently been revived, Viana itself no longer provides the heir with an income. Rather, it symbolizes the historical continuity of the formerCrown of Navarre within the unitedSpanish monarchy.^{[citation needed]}The current holder of the Principality of Viana isPrincess Leonor, daughter ofFelipe VI of Spain and QueenLetizia. Leonor also uses the rest of the traditional titles of the heir of the Spanish Crown:Prince of Asturias,Prince of Girona,Duke of Montblanc andLord of Balaguer.

There are still a few people left with the royal surname of Viana, though they no longer have the Spanish Throne.

• History of the kingdom of Navarre.- The Prince of Viana in Messina
• Medieval History of Navarre.- The Prince of Viana in Naples and Sicily