This qualitative multi-case study explored the space where critical reflection and group development met within the online environment for the adult learner. Using critical reflection with adult learners through their responses to Stephen Brookfield's (1995) Critical Incident Questionnaire (CIQ) in the online environment precipitated instructional effectiveness by unearthing reactions to the online environment and provided a consistent framework for assessing group development. The study context included two sixteen-week, online, asynchronous graduate courses on adult teaching strategies at a research-intensive university located in Midwestern United States. The findings reflected evidence of Tuckman's (1965) and Tuckman and Jensen's (1977) group development sequence of forming, storming, norming, performing, and adjourning within both courses. The analysis and implications were related to critical reflection, group development, the online environment, and adult learning.