Philip IV (April–June 1268 – 29 November 1314), called Philip the Fair (French: Philippe le Bel), was King of France from 1285 to 1314. By virtue of his marriage with Joan I of Navarre, he was also King of Navarre and Count of Champagne as Philip I from 1284 to 1305. Although Philip was known to be handsome, hence the epithet le Bel, his rigid, autocratic, imposing, and inflexible personality gained him (from friend and foe alike) other nicknames, such as the Iron King (French: le Roi de fer). His fierce opponent Bernard Saisset, bishop of Pamiers, said of him: "He is neither man nor beast. He is a statue."

Philip, seeking to reduce the wealth and power of the nobility and clergy, relied instead on skilful civil servants, such as Guillaume de Nogaret and Enguerrand de Marigny, to govern the kingdom. The king, who sought an uncontested monarchy, compelled his vassals by wars and restricted their feudal privileges, paving the way for the transformation of France from a feudal country to a centralised early modern state. Internationally, Philip's ambitions made him highly influential in European affairs, and for much of his reign, he sought to place his relatives on foreign thrones. Princes from his house ruled in Hungary and in the Kingdom of Naples, and he tried and failed to make another relative the Holy Roman Emperor.

The most notable conflicts of Philip's reign include a dispute with the English over King Edward I's duchy in southwestern France and a war with the County of Flanders, who had rebelled against French royal authority and humiliated Philip at the Battle of the Golden Spurs in 1302. The war with the Flemish resulted in Philip's ultimate victory, after which he received a significant portion of Flemish cities, which were added to the crown lands along with a vast sum of money. Domestically, his reign was marked by struggles with the Jews and the Knights Templar. In heavy debt to both groups, Philip saw them as a "state within the state" and a recurring threat to royal power. In 1306 Philip expelled the Jews from France, followed by the total destruction of the Knights Templar in 1307. To further strengthen the monarchy, Philip tried to tax and impose state control over the Catholic Church in France, leading to a violent dispute with Pope Boniface VIII. The ensuing conflict saw the pope's residence at Anagni attacked in September 1303 by French forces with the support of the Colonna family. Pope Boniface was captured and held hostage for several days. This eventually led to the Avignon Papacy of 1309 to 1376.

His final year saw a scandal amongst the royal family, known as the Tour de Nesle affair, in which King Philip's three daughters-in-law were accused of adultery. His three sons were successively kings of France: Louis X, Philip V, and Charles IV. Their rapid successive deaths without surviving sons of their own would compromise the future of the French royal house, which had until then seemed secure, precipitating a succession crisis that eventually led to the Hundred Years' War (1337–1453).

A member of the House of Capet, Philip was born in 1268 in the medieval fortress of Fontainebleau (Seine-et-Marne) to the future Philip III, the Bold, and his first wife, Isabella of Aragon. His father was the heir apparent of France, being the eldest surviving son of King Louis IX.

In August 1270, when Philip was two years old, his grandfather died while on Crusade, his father became king, and his elder brother Louis became heir apparent. Only five months later, in January 1271, Philip's mother died after falling from a horse; she was pregnant with her fifth child at the time and had not yet been crowned queen beside her husband. A few months later, one of Philip's younger brothers, Robert, also died. Philip's father was finally crowned king at Rheims on 15 August 1271. Six days later, he married again; Philip's stepmother was Marie, daughter of the duke of Brabant.

In May 1276, Philip's elder brother Louis died, and the eight-year-old Philip became heir apparent. It was suspected that Louis had been poisoned and that his stepmother, Marie of Brabant, had instigated the murder. One reason for these rumours was the fact that the queen had given birth to her own first son the month Louis died. However, both Philip and his surviving full brother Charles lived well into adulthood and raised large families of their own.

The scholastic part of Philip's education was entrusted to Guillaume d'Ercuis, his father's almoner.