Research on epistemic cognition (EC) focuses on people’s beliefs, stances, or theories related to knowledge and knowing. This chapter discusses learning sciences (LS) approaches to research on EC. Six features of research on EC are relatively distinctive to LS: (1) emphasizing multidisciplinary research, (2) broadening the range of questions, (3) challenging normative assumptions, (4) a focus on practices, (5) the thoroughly social nature of EC, and (6) its situativity. Learning scientists typically investigate EC through promoting and analyzing rich epistemic practices as learners engage with practical reasoning tasks. We illustrate LS approaches to studying epistemic practices by examining the practices of explanation and argumentation at three levels of analysis: the community/system level, the interactional level, and the individual level. Our review of this research reveals the diverse ways in which EC is embedded within social communities. Finally, we highlight the LS theme that EC varies across disciplines by contrasting EC in history and EC in science along the dimensions of epistemic aims, epistemic ideals or criteria, and reliable epistemic processes used to achieve knowledge.