Cornelius Høyer was a Danish painter, mainly known for his work in miniatures. Within his special trade, he was among the virtuosos of his day and won an international reputation.

Høyer was born at the Kronborg Rifle Factory. From an early age he attended the Royal Danish Academy of Fine Arts, studying under Carl Gustaf Pilo and Louis Tocqué, and later continued his education in Paris where Jean-Baptiste Masse taught him miniature painting.

A visit to Italy in 1767 introduced him to Rosalba Carriera and he learned new skills, including the special technique of painting on ivory.

In 1769, Høyer was appointed Miniature Painter to the Danish Court and the following year he became a member of the Academy.