Online learning has grown productive and vital for delivering asynchronous instruction to undergraduate medical students. We explored the factors that affect the learning of undergraduate medical students in an online asynchronous Forensic Medicine course through focus group discussions. These factors were identified in three components of theoretical framework: learner, design, and environment. The promoting factors in the learner component were regulation of learning, internal motivation, metacognition, interaction with peers, and social interaction. Hampering factors were poor self-regulation, losing motivation, and less use of discussion forums. In the environment component students' engagement, external motivation, and lack of physical interaction hampered the learning. In design: course content, links, extra material, pre-recorded lectures, assessment, time limitation, and flexibility promoted the learning, while lack of training in asynchronous mode, losing motivation, loss of attention, and less interaction hampered learning. These identified factors will assist online educators and instructors in designing better online asynchronous courses.