Jean Pierre Étienne Vaucher (17 April 1763 - 6 January 1841) was a Swiss Protestant pastor and botanist who was a native of Geneva.
He studied theology at Geneva, and from 1795 to 1821 was a pastor at the Church of Saint-Gervais. From 1808 to 1840 he was a professor of church history at the University of Geneva, and for several years also taught classes in botany. Among his better-known students were botanist Augustin Pyramus de Candolle (1778-1841), scientist Hans Conrad Escher von der Linth (1767-1823) and Charles-Albert (1798-1849), the future King of Sardinia.
Vaucher is remembered for his research involving developmental history of algae. In his 1803 treatise Histoire des Conferves d'eau douce he described the process of conjugation, which is a means of fertilization that takes place among algae. He also described the development of new networks in the cells of the algae genus Hydrodictyon. His name is lent to Vaucheria, which is a genus of yellow-green algae.