Castelnuovo (Castarnóvo in local dialect) is a comune (municipality) in Trentino in the northern Italian region Trentino-Alto Adige/Südtirol, located about east of Trento. As of 31 December 2004, it had a population of 926 and an area of .
Castelnuovo borders the following municipalities: Telve, Scurelle, Carzano, Borgo Valsugana, Villa Agnedo and Asiago.