Mathematics struggling learners are an important agenda to be solved in mathematics education and the country. Our research purpose is that understand the research trends on mathematics struggling learners have been categorized and flowed. In consideration of this purpose, we examined 782 domestic papers published from 1980 to 2019 using topic modeling to identify the research trend of mathematics struggling learners. The findings indicated that there were different core keywords by period. Additionally, six topics were derived such as ‘Struggling Factors’, ‘Programs for Struggling Learner’, ‘Learning Fractions’, ‘Errors of Struggling Learner’, ‘Instruction Methods’, ‘Supplementary Materials & System’. Additionally, each topic showed a different weight change according to the time series change and hot topics appeared as a teaching method. Based on these findings, we suggest implications for educators and researchers. First, research for struggling learners in other areas of mathematics should be spread. Second, research on the diagnosis of underachievers in mathematics learning needs to be spread. Third, research on social and cultural variables that cause struggling learners in mathematics learning needs to be spread.