Research is limited on how metacognition is facilitated and manifested in socially situated online learning environments such as online discussion forums. We approached metacognition as the phenomenon of interest partly through a methodological objective to evaluate the relevance of a metacognition construct and partly through a content objective to study student-led facilitation of discussions as a strategy in promoting metacognition. Results revealed that the metacognition construct was useful in helping us understand and organize the data and student-led online discussions can be an effective strategy for helping students develop dimensions of metacognition including knowledge, monitoring, and regulation. However, in order for students to use these skills effectively, instruction, motivation, and guidance are needed particularly related to regulation of metacognition and co-construction of meaning.