There are several reasons why putting the “bio” in “biosocial” has the potential to make important contributions to the social and behavioral sciences. First, humans are biological creatures, embedded in families, social networks, communities, and cultures. Context matters to human biology, and engagement with biological concepts and measures reflects this reality. This is especially clear in the case of human health, where the importance of “social determinants” is well-established and widely known (Adler et al. 1994; Glass & McAtee 2006; Link & Phelan 1995), and where social impacts on underlying physiological processes are apparent and increasingly elaborated (Uchino, Cacioppo, & Kiecolt-Glaser 1996; Yang et al. 2016). Attention to biology has the potential to illuminate mechanisms through which socioeconomic, demographic, and psychosocial factors shape human development and health within the contexts of everyday life.