Philip the Handsome (22 June/July 1478 – 25 September 1506), also called Philip the Fair, was the first King of Castile from the House of Habsburg (as Philip I) for a brief time in 1506. He was also ruler of the Habsburg Netherlands from 1482, and additionally ruled over the counties of Artois, Burgundy and Charolais from 1493.

The son of archduke Maximilian of Austria (later Holy Roman Emperor as Maximilian I) and duchess Mary of Burgundy, Philip was not yet four years old when his mother died as a result of a riding accident, and upon her death in March 1482, he inherited her titles, and effective possessions in the Burgundian Netherlands, thus becoming the first Habsburg ruler of those lands, as confirmed by the Treaty of Arras in December 1482. Already in 1493, by the Treaty of Senlis, additional parts of his Burgundian inheritance were secured for Philip, including the counties of Artois, Burgundy and Charolais. Despite his young age, Philip quickly proved himself an effective ruler beloved by his people in the Low Countries, pursuing policies that favored peace and economic development, while maintaining a steady course of the government building.

In 1496, Philip's father arranged for him to marry Joanna, the second daughter of Queen Isabella I of Castile and King Ferdinand II of Aragon. Around the same time, Philip's sister, Margaret, was given in marriage to Joanna's brother John, Prince of Asturias. After the deaths of her brother John, sister Isabella, and nephew Miguel, Joanna became heiress presumptive to the thrones of Castile and Aragon. Most of Philip's time in Spain was spent consolidating his power, often leading to conflicts with his wife and her father. Joanna became queen of Castile when her mother died in 1504. Philip was proclaimed king in 1506, but died a few months later, leaving his wife distraught with grief. Joanna's father, Ferdinand II of Aragon, and her own son, Charles V, Holy Roman Emperor, were quick to seize power, confining the queen for the rest of her life on account of her alleged insanity.

Philip was the first Habsburg monarch in Spain, and every Spanish monarch since his son Charles V has been one of his descendants. Philip died before his father, and therefore never inherited his father's territories or became Holy Roman Emperor. However, his son Charles eventually united the Habsburg, Burgundian, Castilian, and Aragonese inheritances. By inheriting the Burgundian Netherlands and acquiring much of Spain and its possessions in the New World by marriage to Joanna, Philip was instrumental in greatly enhancing the territories of the Habsburgs, and his progeny would rule over vast European territories for the next five centuries.

Philip was also holder of several titular claims on rule over those lands of his Burgundian inheritance that were taken from his mother by the French in 1477, thus claiming the title of the Duke of Burgundy from 1482 to 1506.

Philip was born in Bruges on 22 June/July 1478, the son of the future Maximilian I, Holy Roman Emperor, by his first wife Mary, Duchess of Burgundy. He was born in the County of Flanders (today in Belgium) during the reign of his grandfather Frederick III. When Philip was born, King Louis XI of France, the chief opponent of his parents, spread the rumour that the child was actually a girl, not a boy. When Philip's baptism was organized, his step-grandmother Margaret of York showed the boy naked to the populace, so that any doubt about the child's sex would disappear. The child was named in honour of his maternal great-grandfather, Philip the Good, paternal grandfather of his mother Mary. In his first presentation to the father, the parents expressed double dynastic pride. Mary said: “Sir, look at your son and our child, young Philip of imperial seed.” Maximilian kissed the baby, and replied, “O noble Burgundian blood, my offspring, named after Philip of Valois.”

Philip was only four years old when his mother died in March 1482, resulting in him succeeding all of her titles, and effective possessions in the Burgundian Netherlands, under the guardianship of his father. Already in December 1482, the Treaty of Arras was concluded with the king Louis XI of France, that secured Philip's rule over much of the Low Countries, but also left the Duchy of Burgundy in French possession, and additionally defined the counties of Artois, Burgundy and Charolais as the dowry of Philip's sister Archduchess Margaret of Austria, who was engaged to the French prince.

A period of turmoil ensued which witnessed sporadic hostilities between, principally, the large towns of Flanders (especially Ghent and Bruges) and the supporters of Maximilian. Philip became caught up in events and his custody was taken away by a council appointed by the Netherlandish Estates as part of the larger Flemish campaign to support their claims of greater autonomy, which they had wrested from Mary of Burgundy in an agreement known as the Great Privilege of 1477. It was only in the summer of 1485 that Maximilian, marching into Ghent with German troops and forcing its leader Jan Coppenhole to flee, could embrace his son again. Young Philip was then brought to Mechelen and delivered to the loving care of Margaret of York.