Students who complete homework generally do better on measures of academic performance such as quizzes, exams, and overall course grades. We examined the effects of contingent access to second quiz attempts on the percentage of undergraduate students completing homework to mastery. The study was conducted in an Introduction to Behavior Analysis course that, historically, had only 70% of students on average completing homework. An adapted multiple baseline design across sections was used for four sections of the course. Students could access a second quiz attempt contingent by meeting the following criteria: the student received a 16 out of 20 on the first quiz attempt or by meeting the mastery criterion of the homework (45 out of 50). We also examined the relation between homework accuracy and scores on first quiz attempts. Two sections did not show a difference in homework completion with and without the second quiz attempt contingency. One section showed more sensitivity toward the contingency once it was withdrawn, and one section never had the removal of the contingency and had the highest percentages of students completing their homework. When analyzing the relation of homework accuracy to the corresponding first quiz attempts, homework accuracy appeared to be related to higher scores on first quiz attempts across all sections. Quiz scores were typically a letter grade higher for students who completed homework compared to students who did not complete homework to mastery. Although there are limitations to the current study, the results suggest the second quiz contingency may impact homework completion.