The Titular See of Aqua Flaviae (Portuguese: Sé titular de Aqua Flaviae/Diocese de Aquæ Flaviæ) is a former diocese in the Portuguese district of Vial Real and current titular seat of Chaves.
Around 350 A.D., Aquae Flaviae was suffragan diocese of the Archdiocese of Braga.
The only recorded reference to a bishop was Idácio de Chaves, and the bishopric was suppressed in 711.
The diocese was nominally restored in 1969 as a Latin titular bishopric, and had the following incumbents, of the lowest (episcopal) rank:
This article about a Roman Catholic titular see in Europe is a stub.