Fiera di Primiero was a comune in Trentino in the northern Italian region Trentino-Alto Adige/Südtirol, located about 60 kilometres east of Trento. It was merged with Siror, Tonadico and Transacqua on January 1, 2016, to form a new municipality, Primiero San Martino di Castrozza. With an area of 0.15 square kilometres, Fiera di Primiero was one of the smallest municipalities in land area in Italy.