A portrait miniature is a miniature portrait painting from Renaissance art, usually executed in gouache, watercolor, or enamel. Portrait miniatures developed out of the techniques of the miniatures in illuminated manuscripts, and were popular among 16th-century elites, mainly in England and France, and spread across the rest of Europe from the middle of the 18th century, remaining highly popular until the development of daguerreotypes and photography in the mid-19th century. They were usually intimate gifts given within the family, or by hopeful males in courtship, but some rulers, such as James I of England, gave large numbers as diplomatic or political gifts. They were especially likely to be painted when a family member was going to be absent for significant periods, whether a husband or son going to war or emigrating, or a daughter getting married.

The first miniaturists used watercolour to paint on stretched vellum, or (especially in England) on playing cards trimmed to the shape required. The technique was often called limning (as in Nicolas Hilliard's treatise on the Art of Limming of c. 1600), or painting in little. During the second half of the 17th century, vitreous enamel painted on copper became increasingly popular, especially in France. In the 18th century, miniatures were painted with watercolour on ivory, which had now become relatively cheap. As small in size as 40 mm × 30 mm, portrait miniatures were often fitted into lockets, inside watch-covers or pieces of jewellery so that they could be carried on the person. Others were framed with stands or hung on a wall, or fitted into snuff box covers.

The portrait miniature developed from the illuminated manuscript, which had been superseded for the purposes of book illustration by techniques such as woodprints and calc printing. The earliest portrait miniaturists were famous manuscript painters like Jean Fouquet (self-portrait of 1450), and Simon Bening, whose daughter Levina Teerlinc mostly painted portrait miniatures, and moved to England, where her predecessor as court artist, Hans Holbein the Younger painted some miniatures. Lucas Horenbout was another Netherlandish miniature painter at the court of Henry VIII.

France also had a strong tradition of miniatures, centred on the court, although this came to concentrate in the mid-16th century on larger images, about the range of sizes of the modern paperback book, which might not qualify as miniatures in the usual sense. These might be paintings, or finished drawings with some colour, and were produced by François Clouet (c. 1510 – 1572), and his followers.

The earliest French miniature painters were Jean Clouet (died c. 1540), his son François Clouet, Jean Perréal and others; but of their work in portraiture we have little trace at the present day, although there are many portraits and a vast number of drawings attributed to them. The seven portraits in the Manuscript of the Gallic War (Bibliothèque Nationale) are assigned to the eider Clouet; and to them may be added a fine work, in the Pierpont Morgan collection, representing the Marschal de Brissac. Following these men we find Simon Renard de St. André (1613–1677), and Jean Cotelle. Others whose names might be mentioned were Joseph Werner (1637–1710), and Rosalba Carriera (1675–1757).

The first famous native English portrait miniaturist is Nicholas Hilliard (c. 1537–1619), whose work was conservative in style but very sensitive to the character of the sitter; his best works are beautifully executed. The colours are opaque, and gold is used to heighten the effect, while the paintings are on card. They are often signed, and have frequently also a Latin motto upon them. Hilliard worked for a while in France, and he is probably identical with the painter alluded to in 1577 as Nicholas Belliart. Hilliard was succeeded by his son Lawrence Hilliard (died 1640); his technique was similar to that of his father, but bolder, and his miniatures richer in colour.

Isaac Oliver and his son Peter Oliver succeeded Hilliard. Isaac (c. 1560–1617) was the pupil of Hilliard. Peter (1594–1647) was the pupil of Isaac. The two men were the earliest to give roundness and form to the faces they painted. Peter painted initially very like his father, with tiny, coloured dots, giving the portraits a three-dimensionality. Peter Oliver then developed Isaac's style, loosening the dots, and using softer, broader brush strokes to model the faces. They signed their best works in monogram, and painted not only very small miniatures, but larger ones measuring as much as 10 in × 9 in (250 mm × 230 mm). They copied for Charles I of England (1600–1649) on a small scale many of his famous pictures by the old masters.

Other miniaturists at about the same date included Balthazar Gerbier, George Jamesone, Penelope Cleyn and her brothers. John Hoskins (died 1664) was followed by a son of the same name, who was known to have been living in 1700, since a miniature signed by him and bearing that date is in the Pierpont Morgan collection, representing James FitzJames, 1st Duke of Berwick.