In this research, structural equation modeling and TIMSS data were employed to examine the impact of school belonging on math achievement among secondary students in Japan, Korea, and the United States, with a focus on the roles of math attitude and disorderly behavior. Utilizing SmartPLS 4.0, the study delved into the reliability and validity of the measurement model, the direct and indirect effects within the structural model, and gender differences in these dynamics. The findings indicated that while school belonging directly affected math achievement in the United States, it did not in Japan and Korea. Math attitude, encompassing aspects like enjoyment of math (liking math), math self-concept, and the value placed on math (math value), along with disorderly behavior, emerged as key mediators in this relationship. The study also revealed that the associations between school belonging, math attitude, disorderly behavior, and math achievement were more pronounced in boys than in girls. Implications for educators are discussed.