Theobald II (French: Thibaud or Thibault, Spanish: Teobaldo), called the Young, was Count of Champagne and Brie (as Theobald V) and King of Navarre from 1253 until his death.
Theobald was the eldest son of Theobald I of Navarre and his third wife, Margaret of Bourbon. He succeeded to his father's titles on his death at only fourteen years of age. His mother acted as regent with James I of Aragon until 1256, when Theobald came of age. On 27 November, he affirmed the Fueros of Navarre, which limited his power by putting him under the counsel of a tutor from among the aristocracy. He could not make judgements without a council of twelve (a jury) of noblemen. Theobald was not content, however, to be so restricted in royal prerogative before his twenty-first birthday. He received the rites of unction and coronation from Pope Alexander IV in 1257 and 1259 respectively and tried to justify his divine right to rule, a concept foreign until that point in Navarrese politics.
In July 1270, Theobald embarked with his father-in-law on the Eighth Crusade to Tunis. Louis died of dysentery at the siege. Theobald died childless at Trapani in Sicily while returning that same year. He was succeeded by his younger brother, Henry I. His widow Isabella returned home to France, where she died a few months later.