The Sayaca Tanager is the southern and eastern replacement of the Blue-grey Tanager (Thraupis episcopus) to which it is very similar. In the few areas where the two might occur together, the Sayaca is told by its blue shoulder while the Blue-grey has a white shoulder. There are many variations of colour on the shoulder. For example, the subspecies of Blue-grey that I knew in Pereira, Colombia, had a blue shoulder patch.

In south-east Brazil note the similarity with the Azure-shouldered Tanager Thraupis cyanoptera. This has a larger bill, a deep blue shoulder (sometimes difficult to see) and a greenish tinge on the flanks.