Theobald IV of Champagne (1201–1253), known as "the Troubadour," "the Chansonnier," and "the Posthumous," was Count of Champagne and the King of Navarre from 1235. He was the son of Theobald III of Champagne and Blanche of Navarre . His father died before he was born, and Theobald's mother ruled as regent until Theobald turned 21 in 1222.

The first half of Theobald's life was plagued by a number of difficulties. His uncle, count Henry II had left behind a great deal of debt, which was far from paid off when Theobald's father died. Further, Theobald's legitimacy was not unquestioned, and his right to the succession was challenged by Henry's daughter Philippa and her husband, Erard I of Brienne, count of Ramerupt and one of the more powerful Champagne nobles.

The conflict with the Brienne's broke into open warfare in 1215, and was not resolved until after Theobald came of age in 1222. At that time he bought out their rights for a substantial monetary payment. Some years later, in 1234, he had to spend still more to buy off Philippa's younger sister Alice. The 1222 settlement did not end Theobald's problems, for in the following years he antagonized Louis VIII.

At the death of Louis VIII, his political situation was difficult: he had abandoned the king in his campaigns, there were rumors that he had poisoned him, and barons from Normandy and the old domain managed to bock his invitation to the coronation of Louis VIII. At the beginning of the regency of Blanche of Castile, he abandoned a conspiracy agains the Capet, which also included Hugues de Lusignan and Pierre Mauclerc, and cemented a strong relation with the regent. Many have hinted at a possible love for Blanche, and he wrote a poetical homage to her. He became so influential at court, that other barons resented him and started a rebellion in 1229.

In the following years he antagonized the young king of France Louis IX, which lead to an invasion of Champagne by a group of French barons. They were driven off at the cost of further expense and hardship in Champagne. Thus in order to settle with Alice, Theobald had to sell his overlordship over the counties of Blois, Sancerre, and Chateaudun to the king.

However in 1234 Theobald succeeded his grandfather as king of Navarre. This greatly increased his resources (not to mention his prestige), and the remaining years of his rule were far more peaceful and prosperous.

Theobald married three times. He married Gertrude of Dabo in 1220, and divorced her 2 years later when he came of age. Later in 1222 he married Agnes of Beaujeu . After she died in 1231, he married Margaret of Bourbon (1232).

He was succeeded first by his elder son Theobald V of Champagne and then by his younger son Henry III of Champagne. (Both children of his third marriage.)