Karel van Mander III was a Dutch Golden Age painter and the grandson of Karel van Mander.

Karel van Mander III was born in Delft. According to Houbraken, who confused him with his father Karel van Mander the Younger, he learned to paint from his father and became a good portrait painter. His portrait of Christian IV was honored with a poem by Joost van den Vondel. His portrait of Vondel with gray hair in the same year was also rewarded with a Vondel poem.

He was a pupil of his father and was influenced by Frans Hals. He worked in Copenhagen in 1631, and travelled to Italy from 1635-1638. When he returned North he settled in Copenhagen in the company of Abraham Wuchters. He is registered in Amsterdam in 1657. He died in Copenhagen.