Charles IV (18/19 June 1294 – 1 February 1328), called the Fair (le Bel) in France and the Bald (el Calvo) in Navarre, was the last king of the direct line of the House of Capet, King of France and King of Navarre (as Charles I) from 1322 to 1328. Charles was the third son of Philip IV; like his father, he was known as "the fair" or "the handsome".

Beginning in 1323 Charles was confronted with a peasant revolt in Flanders, and in 1324 he made an unsuccessful bid to be elected Holy Roman Emperor. As Duke of Guyenne, King Edward II of England was a vassal of Charles, but he was reluctant to pay homage to another king. In retaliation, Charles conquered the Duchy of Guyenne in a conflict known as the War of Saint-Sardos (1324). In a peace agreement, Edward II accepted to swear allegiance to Charles and to pay a fine. In exchange, Guyenne was returned to Edward but with a much-reduced territory.

When Charles IV died without a male heir, the senior line of the House of Capet, descended from Philip IV, became extinct. He was succeeded in Navarre by his niece Joan II and in France by his paternal first cousin Philip of Valois. However, the dispute on the succession to the French throne between the Valois monarchs descended in male line from Charles's grandfather Philip III of France, and the English monarchs descended from Charles's sister Isabella, was a factor of the Hundred Years' War.

By virtue of the birthright of his mother, Joan I of Navarre, Charles claimed the title Charles I, King of Navarre. From 1314 to his accession to the throne, he held the title of Count of La Marche and was crowned King of France in 1322 at the cathedral in Reims. Unlike Philip IV and Philip V, Charles is reputed to have been a relatively conservative, "strait-laced" king – he was "inclined to forms and stiff-necked in defence of his prerogatives", while disinclined either to manipulate them to his own ends or achieve wider reform.

Charles married his first wife, Blanche of Burgundy, the daughter of Otto IV, Count of Burgundy, in 1308, but Blanche was caught up in the Tour de Nesle scandals of 1314 and imprisoned. After Charles assumed the throne he refused to release Blanche, their marriage was annulled, and Blanche retreated to a nunnery. His second wife, Marie of Luxembourg, the daughter of Henry VII, the Holy Roman Emperor, died following a premature birth.

Charles married again in 1325, this time to Jeanne d'Évreux: she was his first cousin, and the marriage required approval from Pope John XXII. Jeanne was crowned queen in 1326, in one of the better recorded French coronation ceremonies. The ceremony represented a combination of a political statement, social event, and an "expensive fashion statement"; the cost of food, furs, velvets, and jewellery for the event was so expensive that negotiations over the cost were still ongoing in 1329. The coronation was also the first appearance of the latterly famous medieval cook, Guillaume Tirel, then only a junior servant.

During the first half of his reign Charles relied heavily on his uncle, Charles of Valois, for advice and to undertake key military tasks. Charles of Valois was a powerful magnate in his own right, a key advisor to Louis X, and he had made a bid for the regency in 1316, initially championing Louis X's daughter Joan, before finally switching sides and backing Philip V. Charles of Valois would have been aware that if Charles died without male heirs, he and his male heirs would have a good claim to the crown.

Charles came to power following a troublesome two years in the south of France, where local nobles had resisted his elder brother Philip V's plans for fiscal reform, and where his brother had fallen fatally ill during his progress of the region. Charles undertook rapid steps to assert his own control, executing the Count of L'Isle-Jourdain, a troublesome southern noble, and making his own royal progress. Charles, a relatively well educated king, also founded a famous library at Fontainebleau.