Jacobus Buys was a Dutch painter and engraver.
Buys was born in Amsterdam the son of a wig-maker. He studied under Cornelis Pronk, Jacob de Wit, and Cornelis Troost, and ultimately became director of the Amsterdam Drawing Academy. He painted portraits, bas-reliefs, and tapestry, designed book-illustrations, and made copies of the works of the best masters of the seventeenth century. Buys became a member of Amsterdam's Guild of St Luke in 1750, and died in 1801.