Language acquisition and World Englishes (WEs) research are two subdisciplines with their own theoretical approaches, classifications, terminologies, and methodologies for investigation. They also have distinct perspectives on otherwise similar phenomena, viz. manifestations of acquiring/learning a language. As early as 1986, Sridhar and Sridhar discerned “a lack of articulation between theories of SLA and research on the acquisition and use of IVEs [indigenized varieties of English]” (Sridhar and Sridhar 1986: 12) and prompted an integrated approach. However, this call remained largely unheard for about twenty years. Only quite recently have studies pointed to potential similarities and the connectedness of learner Englishes and WEs as well as the possibility, if not necessity, of an integrated approach to the two objects of inquiry. The current chapter provides a scholarly review of these developments. It starts out with a summary and discussion of the potential and need for an integration of the Second Language Acquisition and WEs research paradigms, ultimately expanding the focus to a joint treatment of WEs and First Language Acquisition research.