This article reviews past empirical studies on the use of audio podcast (hereby referred to as podcast) in K-12 and higher education settings. Using the constant comparative method, this review is organized into three major research areas or topics: (a) participants' podcast usage profile, (b) effects of podcast on learners' outcomes, and (b) institutional aspects. Findings suggest that the most common use of podcasting is limited to either instructors distributing podcast recordings of lectures or supplementary materials for students to review subject material at their own time and place. A majority of the previous studies were descriptive, and were conducted in higher education and traditional course settings. Students generally enjoy using podcast, and tend to listen to the podcasts at home using desktop computers, rather than on the move (e.g., commuting to school) with a mobile device. Probably the main benefit of podcasting is that it allows students to listen to specific material that they missed or did not understand multiple times. The availability of podcast does not appear to encourage students to skip classes. We also discuss limitations of previous empirical studies, and provide some directions for future research related to the use of podcast in education settings.