Students' engagement in math is essential for enhancing the effectiveness of math instruction. Previous studies examined the factors influencing math engagement, including parents, teachers, and students, however, few conducted a joint analysis of these variables. This study aimed to investigate the effects of these variables on math engagement by developing a moderated mediation model. A total of 1178 high school students and their primary caregiver (either father or mother) were involved in this study. The findings revealed the following: (1) Parental anxiety does not act as a direct predictor of math engagement; (2) Math anxiety fully mediates the relationship between parental anxiety and math engagement; and (3) Perceived teacher support does not significantly moderate the relationships between parental anxiety and math engagement or between parental anxiety and math anxiety. However, it does have a moderating effect on the relationship between math anxiety and math engagement. These results suggest that enhancing teacher support in math education may effectively reduce math anxiety and subsequently increase students' engagement in math.