Rosy Wertheim was a Dutch pianist, music educator and composer. Rosalie Marie Wertheim was born in Amsterdam to parents John and Adriana Rosa Gustaaf Wertheim Enthoven. Her father was a banker and Rosalie attended a French boarding school in Neuilly where she took piano lessons. She studied piano with Ulfert Schults and harmony and counterpoint with Bernard Zweers and Sem Dresden. In 1921 she took the state exam in piano and graduated from the Nederlandse Toonkunstenaars Vereniging.