This randomized control trial examined the efficacy of team-based learning implemented within 11th-grade social studies classes. A randomized blocked design was implemented with 26 classes randomly assigned to treatment or comparison. In the treatment classes teachers implemented team-based learning practices to support students in engaging in dialogue about course content, application of content to solve problems, and use of evidence to support responses. Significant differences in favor of the treatment group on content acquisition were noted (Hedges's g = 0.19). Examination of differences in response to the treatment indicated groups of students classified with high or moderate pretest scores benefitted from the treatment, whereas a group of students classified with low pretest scores did not benefit from the treatment.