Louis Marie Adolphe Olivier Édouard Joubin (27 January 1861 in Épinal – 24 April 1935) was a professor at the Muséum national d'Histoire naturelle in Paris. He published works on nemerteans, chaetognatha, cephalopods, and other molluscs.
He served as an assistant to Henri de Lacaze-Duthiers, subsequently becoming director of the laboratories at Banyuls-sur-Mer (1882) and Roscoff (1884). Later on, he became an instructor at the University of Rennes, and in 1903 succeeded Edmond Perrier as chaire des mollusques, des vers et des zoophytes at the Muséum national d'Histoire naturelle (from 1917 onward his title was chaire des mollusques). In 1906 he was chosen by Albert I, Prince of Monaco to be in charge of instruction at the Institut océanographique.
In 1905 he was named president of the Société zoologique de France. In 1920 he became a member of the Académie des Sciences.
Joubin's squid (Joubiniteuthis portieri) is named for him, as is Scolymastra joubini, an hexactinellid sponge whose lifespan is purportedly 10,000 years.