This study investigated the effects of self-monitoring on the homework completion and accuracy rates of three fifth-grade low-achieving students in mathematics. A multiple probe design across subjects was utilized to examine two dependent variables: completion and accuracy of math homework. Data were collected and analyzed during baseline, intervention, and maintenance. When student’s homework completion rate remained stable at the baseline stage, intervention began. During intervention, students self-monitored themselves at home and at school, and took part in a brief conference with teacher to review their self-monitoring sheets. To identify whether the effects of intervention continued, a maintenance test was conducted one week after the intervention. The findings are as follows. First, self-monitoring intervention improved low-achieving students’ math homework completion and it was maintained after the intervention was terminated. Second, self-monitoring intervention improved low-achieving students’ math homework accuracy and it was maintained after the intervention was terminated. These results suggest that self-monitoring used in home and school brings improvement of homework completion and accuracy of low-achieving students in math. The study has also proved that the improved homework performance were maintained even after the intervention were over. This result implied that students can manage their homework performance independently through self-monitoring without teacher’s and parent's support. Additionally, future research could investigate the effects of the two self-monitoring components used alone, and investigate the effects of self-monitoring in a natural homework situation in general classrooms with other academic subjects. Also, improvement of academic achievement could be investigated after having students perform homework with self-monitoring interventions.