Reflection is essential to deep learning and problem solving. From a socio-cultural perspective, reflection is developed through social interaction and semiotic mediation (Vygotsky, 1978; Wells, 1999). To reflect, students need to be given opportunities to review their own and others' mental processes and to use techniques such as writing or verbal reports to organize and revise thoughts (Cobb, Boufi, McClain, & Whitenack, 1997). This paper reviews strategies for supporting reflection in online environments, primarily focusing on journaling / blogging and small group asynchronous discussion. We discuss how these strategies support reflection, and survey studies that investigate the effectives of the two strategies. We also provide suggestions for guidance and evaluation of reflection with online learning environments. [For the complete volume, "Educational Media and Technology Yearbook, Volume 34," see ED602586.]