Calls to diversify second language acquisition (SLA) (e.g., Ortega, 2013) have led to increased interest in multilingualism and inclusion of groups less represented in samples of university students, such as individuals at older ages. Nevertheless, we still have more questions than we do answers. This article outlines a research agenda targeting older adult language learning and multilinguals at older ages, both in and beyond the classroom. Since a key difference between young and older adults is cognitive aging, I follow a cognitive approach, focusing on how individual differences in cognition may affect language and vice versa, and how relevant sociocultural factors add to the interplay between language and cognition. Notably, this is not always a story of decline and deficits, but instead of both strengths and weaknesses that differ from those of young adults.