Gerard Horenbout or Gerard Hourenbout was a Flemish miniaturist, a late example of the miniature tradition in Early Netherlandish painting. He is "likely and widely accepted" to be the Master of James IV of Scotland, a leading miniaturist of the period, responsible for the Spinola Hours and other major projects of the last flowering of the Flemish miniature tradition.

Horenbout lived and worked in Ghent and is best known as a manuscript illustrator. He also made stained glass, tapestries, embroidery designs, ironworks and panel painting. First mentioned in 1487, when he joined the painters Guild of Saint Luke. He was married to Margaret Svanders soon after joining the guild. They had six children, two of whom were the artists Lucas Horenbout and Susanna Hornebolt. There were also sons Eloy and Joris. Lucas, Susanna and at least one more of his sons were trained by Horenbout to be painters.

He had at least two apprentices, one in 1498, and one in 1502. In 1515, he was made painter to Archduchess Margaret of Austria, and also briefly worked at the court of Henry VIII in England. He was visited by Albrecht Dürer in 1521, when Dürer bought an illustrated manuscript made by his daughter Susanna Horenbout. His son Lucas Horenbout was also a well-known painter.

His wife, Margaret Svanders, or van Saunders, died in 1529 and he made the brass plaque found at All Saints' Church in Fulham, London.

He died about 1540 or 1541.