Umberto Zannier (born 25 May 1957, in Spilimbergo, Italy) is an Italian mathematician, specializing in number theory and Diophantine geometry.

From 2003 to the present he has been a Professor in Geometry at the Scuola Normale Superiore di Pisa.

Thus they gave a new proof of the Manin–Mumford conjecture (which was first proved by Michel Raynaud and Ehud Hrushovski).

[5] In 2005 Zannier received the Mathematics Prize of the Accademia dei XL and in 2011 an Advanced Grant from the European Research Council (ERC).

He is chief editor of the Annali di Scuola Normale Superiore and a co-editor of Acta Arithmetica.