Interteaching is a behavioral teaching method that has been empirically shown to increase student learning outcomes. The present study investigated the effect of combining interteaching with cumulative versus noncumulative exams in two sections of an online asynchronous class. Interteaching was used in both sections of the course. The noncumulative exam section experienced weekly exams with test questions that only covered material learned in that week of class. The cumulative exam section was given weekly exams in which half of the questions were from material learned that current week and the other half were cumulative up to that point in the class. This was followed by a cumulative final exam given to both groups. All exam questions were multiple choice. On average, students in the cumulative exam group scored 4.91% higher on the final exam than students in the noncumulative exam group. Students exposed to weekly cumulative exams also earned more As and Bs on the final compared to the noncumulative exam group. Overall, our experiment provides evidence that interteaching may be further improved when combined with cumulative weekly exams.