(1498 - 1 October 1574) was a Dutch portrait and religious painter, known for his depictions of the Seven Wonders of the World.
He was born at Heemskerk, North Holland, halfway between Alkmaar and Haarlem.
His father was a small farmer, Jacob Willemsz. van Veen (whose portrait he painted). According to his biography, written by Karel van Mander, he was apprenticed to Cornelis Willemsz in Haarlem. Recalled after a time to the paternal homestead and put to the plough or the milking of cows, young Heemskerk took the first opportunity that offered to run away, and demonstrated his wish to leave home for ever by walking in a single day the 80 km which separate his native hamlet from the town of Delft. There he studied under Jan Lucasz whom he soon deserted for his contemporary Jan van Scorel of Haarlem. Even today, many of Heemskerck's paintings are mistaken for work by van Scorel. He boarded at the home of the wealthy Pieter Jan Foppesz (the van Mander spelling is Pieter Ian Fopsen), curate of the Sint-Bavokerk. He knew him because he owned a lot of land in Heemskerck. This is the same man whom he painted in a now famous family portrait, considered the first of its kind in a long line of Dutch family paintings.