This paper reviews findings of some studies of heritage Portuguese bilingualism (both European and Brazilian Portuguese), with a focus on morphosyntax, and reflects on some theoretical observations about heritage bilingualism. We conclude that there is mostly successful heritage language acquisition among the heritage speakers considered in each study, although one can still observe variability depending on the linguistic phenomenon, similarly to what happens in other speaker communities. The picture emerging from these studies indicates that there is no overarching trend towards incomplete acquisition, reduced ‘complexity’ or simplification across linguistic domains. This is particularly relevant regarding appeal to incomplete acquisition, given that it is not possible to apply such a concept formally and epistemologically, because one cannot define deterministically what counts as a complete grammatical system (Pires 2011).