Reported incompetence of student teachers in Nigeria has become a national concern. However, little has been done to explore the mitigating factors to student teachers' academic success, especially from the generic qualitative approach. The present study adopted the interpretive descriptive qualitative design to examine factors affecting the academic achievement of underachieving student teachers in a Nigerian university. Semistructured interviews were employed in the data generation process. The study sample included 30 underachieving student teachers in the Department of Educational Foundations who were enrolled in the English/Education option. Using thematic content analysis, researchers reported factors such as lecturers' pedagogical incompetence, noisy and inadequate classrooms/libraries, negative influences from friends, students' lack of motivation and interest, procrastination, poor study habits, laziness and distractions, poor socio-economic background, and parental pressure contributed to students' underachievement. These factors were categorized as school, peer, personal, and home-related. Study results indicated that the interplay of forces outside the mental abilities of the students may have impeded their academic success, deepening our understanding that underachievement may not necessarily result from low mental ability.