Heather Menzies-Urich (born Heather Margaret Brotherston Menzies; December 3, 1949 – December 24, 2017) was a Canadian-American actress and model, known internationally for her role as Louisa von Trapp in the 1965 musical film *The Sound of Music*. Although this remains her most iconic role, her career continued with appearances in numerous television series and films. Her most significant performances include Jessica 6 in the science fiction series *Logan's Run* (1977–1978) and a leading role in the cult horror film *Piranha* (1978), directed by Joe Dante. After marrying actor Robert Urich, she gradually reduced her acting appearances. Following her husband's death from a rare form of cancer, she established the Robert Urich Foundation, actively dedicating herself to fundraising for cancer research and supporting cancer patients. This commitment defined the latter part of her life and stands as a significant recognition of her work outside the entertainment industry.