The theory of social presence is perhaps the most popular construct used to describe and understand how people socially interact in online learning environments. However, despite its intuitive appeal, researchers and practitioners alike often define and conceptualize this popular construct differently. In fact, it is often hard to distinguish between whether someone is talking about social interaction, immediacy, intimacy, emotion, and/or connectedness when they talk about social presence. Therefore, this chapter outlines the evolution of the construct of social presence in an effort to understand better its relationship to online learning.