This study investigated the role of debriefing as a form of reflection in promoting affective and cognitive learning in simulation games. Debriefing is central to the experiential learning process, yet simulation game research studies seldom have focused on it. A well-designed simulation game with debriefing potentially provides a means to engage students in thoughtful, engaging, and worthwhile learning that is consistent with the contemporary goals of social studies education. A small number of prior studies found debriefing had a positive effect on cognitive learning. However, the studies with positive results concerning debriefing are too few and too contradictory as a result of problematic designs to warrant generalizations from the findings. The participants for this study were 238 high school students in state mandated economics classes in Georgia public schools. A variety of immediate and retention posttest measures were utilized to assess the levels of cognitive learning and interest on four randomly assigned alternative treatments: oral debriefing, written debriefing, combined written and oral debriefing, or no debriefing. Data were analyzed by means of descriptive statistics, analysis of variance, and effect sizes. Findings from this sample supported previous research results that indicated debriefing has a positive immediate effect on cognitive learning. However, the results from this experiment showed small observed differences for the debriefing treatments relative to the control of no debriefing. Effect sizes were typically small and most differences were not statistically significant. The implications of the results and suggestions for future research were discussed in detail.