Bruno Valentini (born 29 May 1955 in Colle di Val d'Elsa) is an Italian politician.
Valentini started his political career in Siena and then as a municipal councillor in Monteriggioni, Tuscany, in 1995. He served as Mayor of Monteriggioni from 2004 to 2013. He has been a member of the Democratic Party since 2007.
Valentini was elected Mayor of Siena on 11 June 2013. He ran for a second term at the 2018 Italian local elections, but was defeated by the centre-right candidate Luigi De Mossi.