Betsy Westendorp-Osieck (1880-1968) was a Dutch painter, watercolorist, etcher, pastelist and draftsman who was part of the Amsterdamse Joffers painting group.
Johanna Elisabeth ("Betsy" or "Betsie") Osieck was born in Amsterdam 29 December 1880 to the merchant Philip Willem Osieck and Catharina Agnes Briel.
She was one of a family of five, but one of them died as a child. Westendorp-Osieck attended a French secondary school before going to a German boarding school.
She intended becoming a pianist but when that proved improbable she took up art.