Learners' feelings of social connectedness may be a key factor in predicting online course success. However, students attempting to perceive and process the social context in online courses often find themselves engaging in unfamiliar, technology-mediated communication channels. While there have been several empirically based strategies published for creating and maintaining social connectedness online, presently there are no validated instruments available to evaluate the success or failure of the pedagogical methods employed. This article reports on the development and initial technical validation of the Social Perceptions in Learning Contexts Instrument (SPLCI), a research tool for measuring students' perception of social connectedness with participants in online courses. Findings demonstrated strong validity and reliability evidence that collectively supports continued development of the SPLCI. (Contains 7 tables.)