Jean Pierre Étienne Vaucher (17 April 1763 – 5 or 6 January 1841) was a Swiss Protestant pastor and botanist who was a native of the Republic of Geneva.
From 1808 to 1840 he was a professor of church history at the University of Geneva, and for a number of years he 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 the developmental history of algae.
The phenomena of conjugation is a means of fertilization that takes place in green algae such as Spirogyra.