Adriaen Thomasz. Key (c. 1544, Antwerp – after 1589, Antwerp) was a Flemish painter of portraits and religious paintings, a draughtsman and a printmaker. He worked for a while in the Antwerp workshop of the prominent history and portrait painter Willem Key and later took over the workshop. His work was highly regarded in his time for its technical mastery and innovative concepts and thus influenced a later generation of painters including Rubens.