Betsy Westendorp-Osieck (29 December 1880 – 1 March 1968) was a Dutch painter, watercolourist, etcher, pastelist and draftsman who was part of the Amsterdamse Joffers painting group.

She went on to study in Amsterdam at the Teekenschool voor den Werkenden Stand from 1905 to 1910 and at the State Academy of Fine Arts.

Her first commission was to draw a certificate for the Amsterdam cradle for Princess Juliana made by Karel de Bazel in 1909.

As an etcher Westendorp-Osieck created a number of illustrations of the "Old Amsterdam garden houses" which was published by Bernard Houthakker in 1923.

[3][4][5][8] Her work was included in the 1939 exhibition and sale Onze Kunst van Heden (Our Art of Today) at the Rijksmuseum in Amsterdam.