Otto van Veen, also known by his Latinized name Otto Venius or Octavius Vaenius, was a painter, draughtsman, and humanist active primarily in Antwerp and Brussels in the late 16th and early 17th centuries. He is known for running a large studio in Antwerp, producing several emblem books, and for being, from 1594 or 1595 until 1598, Peter Paul Rubens' teacher. His role as a classically educated humanist artist, reflected in the Latin name by which he is often known, Octavius Vaenius, was influential on the young Rubens, who would take on that role himself.