We connect research on sociolinguistic competence and its development during study abroad to the study of heritage speakers in this learning context. Sociolinguistic competence encompasses all of the mechanisms that speakers use to communicate in situationally appropriate ways. We begin with an overview of sociolinguistic competence, particularly as it develops in various contexts of learning. We then seek to characterize the competence that heritage speakers bring to study abroad, such as knowledge of interactional patterns in a particular interactional context (e.g., at home) and possible access to multiple varieties of Spanish. Our research synthesis informs the agenda that we outline for future research on heritage speakers abroad. We call on previous research to provide models for future investigations of second- and heritage-language learners. We conclude this chapter by discussing the impact that this line of research will have on related pursuits. For example, this research can inform variationist theory and research on bilingualism and social aspects of language use more broadly.