Research on equity has received a great amount of attention in the field of mathematics education. Although various review studies have focused on race/ethnicity issues in mathematics education, they rarely examined how the studies on race/ethnicity issues in mathematics education have evolved over time. This study examined research topics and trends of race/ethnicity studies in mathematics education while drawing on a social-ecological model. We collected 920 articles in the field of mathematics education that are relevant to the issue of race/ethnicity during the last 2 decades and implemented a topic modelling method. Findings include 11 latent topics, which were classified into 4 levels of the social-ecological model: individual ("Growth," "Identity"), interpersonal ("Immigrants," "English language learners"), community ("Kindergarten," "Course taking and college," "Culturally responsive teaching," "Intervention," "School programme and instructional practices"), and societal ("Stereotype threat," "Segregation"). Among the topics, "Identity" and "Stereotype threat" were getting more attention as hot topics, while "Course taking and college" and "School programme and instructional practices" are becoming gradually less popular. The implications were discussed related to equity issues in the field of mathematics education.