Homework is an important out-of-class activity, crucial to student success in engineering courses. However, in a first-semester freshman engineering course, approximately one-fourth of students were completing less than 80% of the homework. The purpose of this study was to examine students' attribution of their low completion of homework and suggest corresponding interventions to help students with different attribution types. A qualitative approach was applied using semi-structured interviews for data collection. The interviewees were students who were on track to complete less than 80% of the homework. Students in the study attributed their low rates of completion to multiple factors. We coded and summarized students' attributions of homework incompletion according to Weiner's attribution theory and suggested corresponding interventions for students with different attribution types. Results show that most students attributed their failure to complete their homework to external reasons rather than internal reasons. A large portion of student's attributions for low homework completion was due to poor time management skills. Some students attributed low homework completion to unstable factors such as illness, transition, or adjustment problems. A small portion attributed low homework completion to uncontrollable reasons, such as sickness and homework difficulty. Students' reasons for homework incompletion varied across the three dimensions of Weiner's attribution theory suggesting that a variety of intervention techniques is required. In addition to use of widely adopted interventions such as first-year seminars, tutoring, and tutorial sessions, intervention techniques based on attribution theory may be necessary to employ, to help students avoid negative emotional and behavioral consequences of homework incompletion.