Juan de Flandes (c. 1460 – by 1519) ('John of Flanders') was an Early Netherlandish painter who was active in Spain from 1496 to 1519; his actual name is unknown, although an inscription Juan Astrat on the back of one work suggests a name such as "Jan van der Staat". Jan Sallaert, who became a master in Ghent in 1480, has also been suggested.
He was born around 1460 in Flanders (modern Belgium), and evidently trained there, most likely in Ghent, as his work shows similarities to that of Joos van Wassenhove, Hugo van der Goes and other Ghent artists. He is only documented after he became an artist at the court of Isabella I of Castile in Spain, where he is first mentioned in the accounts in 1496, and described as "court painter" by 1498, continuing in her service until her death in 1504. He mostly painted accomplished portraits of the royal family, but also most of a large group of small (21.3 x 16.7 cm) panels for a polyptych altarpiece for Isabella, now widely dispersed with the largest group of panels in the royal collection in Madrid. After Isabella's death in 1504 he turned to ecclesiastical work for Spanish churches, in Salamanca in 1505-7, and thereafter based in Palencia, where there is a large reredos in the Cathedral and where his wife is described as a widow in December 1519. The overwhelming majority of his work held in collections outside Spain comes from this later period in which he concentrated on religious themes. Panels from a large altarpiece from a Palencian church are divided between the Prado and National Gallery of Art, Washington, who have four each. His works show the Early Netherlandish style of Ghent adapted to Spanish taste and landscape, notably the requirements for groups of compartmented scenes for altarpieces. His colouring is refined, "with a preference for rather acid hues", and "while his feeling for space and light is sophisticated, a tendency to divide space into a succession of thin planes becomes a mannerism in his late works".