Although previous research has found interteaching to be an effective form of instruction, all of the currently published data have been collected in courses that have allowed for a minimum of 48 hours between class sessions. In the current study, we examined the effectiveness of interteaching compared to traditional lecture during a six week summer session of a behavior modification course. Two non-concurrent sections of the behavior modification course were taught during which the instructor alternated between interteaching and traditional lecture. These courses were counterbalanced, such that when material from one section was covered using an interteaching approach, the same material in the other section was presented using a traditional lecture. Unlike previous studies, students did not score higher on exams following interteaching sessions. Nevertheless, students did indicate that they found interteaching to be beneficial. Interpretations of these results, the social validity responses, practical implications, and recommendations for additional research are discussed.