The present study reviewed the papers in the Scopus database relevant to flipped classrooms in all mathematics subject areas published up until 2018 from various dimensions. It was found that there has been a considerable number of studies on flipped classrooms in mathematics education in these years. The majority were conducted in university courses, such as applied mathematics, discrete mathematics/algebra, and analysis. Most of the researchers adopted quantitative methods. In the before-class stage of the mathematics flipped classroom, a number of studies employed online learning systems or social media to provide instructional videos and to carry out online discussion. As for the in-class stage, the most frequently adopted learning strategies were issue discussion, exercise, and problem-based learning, while only a few studies used technologies in this stage. The majority of studies investigated students' learning achievement, motivation, satisfaction, and collaboration and communication awareness. Most studies administered examinations to evaluate the students' learning achievement. It is worth noting that little or no research was found to explore students' cognitive load. Accordingly, several suggestions for applying flipped classrooms to mathematics education as well as potential issues for future research are proposed in this study.