Social support and face-to-face learning may enhance outcomes for students who face barriers in accessing Massive Open Online Courses (MOOCs). This study investigated how self-identified volunteer leaders guide and foster interactions among small groups of students who face technical and conceptual barriers in accessing MOOC content. Several months prior to the start of the MOOC (Environmental Education: Transdisciplinary Approaches to Addressing Wicked Problems), registered students volunteered to lead small groups for participants whose primary language was other than English and where limited Internet access and cultural barriers curtailed access to and understanding of course materials and pedagogy. Results of a survey and in-depth interviews (N = 10) revealed that group leaders were instrumental in overcoming barriers related to language, content, cultural ways of learning, access, and time. Group leaders also fostered cooperative learning strategies, which helped students acquire course content, and encouraged collaborative group projects leading to groups adopting some features of online knowledge communities. The term "social learning MOOC" (slMOOC) is proposed to capture a growing trend of incorporating collaborative learning strategies in xMOOCs and to emphasize how MOOCs use interactive learning strategies to help students apply course content to local contexts and thus may contribute localized knowledge to globalized MOOC learning environments.