Collagna (Emilian: Culâgna) is a frazione (borough) of the comune (municipality) of Ventasso in the Province of Reggio Emilia in the Italian region Emilia-Romagna, located about 90 kilometres (56 mi) west of Bologna and about 50 kilometres (31 mi) southwest of Reggio Emilia. It was a separate comune until 1 January 2016, when it was merged with Busana, Ligonchio and Ramiseto.

Collagna borders the Tuscan municipalities of Comano (MS), Fivizzano (MS) and the former municipality of Sillano (LU).

• Giovanni Lindo Ferretti (b. 1953), singer-songwriter, born in Cerreto Alpi