Sijtje Antje Agatha Johanna Aafjes was a Dutch painter, draftswoman, and illustrator, mainly of children's books.
Her parents were Margje van der Heijden (1871–1934) and Anthonius Pieter Aafjes (1864–1934).
In 1919, she worked in Katendrecht at the Openbare Bewaarschool aan de Tolhuisstraat.
[2] During her time teaching, she became a self-taught artist, making paintings and illustrations.
[2] She was mentored by the artist Berhardina Midderigh-Bokhorst, whom Aafjes was introduced to by a publisher.