Background <p>Research on the relationship between growth mindset and mathematics achievement is heterogeneous and even contradictory, especially in China. Previous studies have typically directly analyzed the relationship between the two factors, rather than exploring the impact of growth mindset on mathematics achievement through mediating mechanisms. The current study aimed to explore the relationship between growth mindset and mathematics achievement, as well as the chain mediating roles of achievement goals and grit.</p> Methods <p>This study used a cross-sectional design with convenience cluster sampling. All first-grade students (Grade 7) from a public middle school in China, were invited to participate, resulting in a final sample of 691 participants. They completed a questionnaire assessing growth mindset, achievement goals, and grit. Their mathematics test scores were also collected. Statistical data analysis was performed using SPSS 27.0, including an analysis of the chain mediation effect through the PROCESS program developed by Hayes.</p> Results <p>A growth mindset was found to be significantly negatively correlated with mathematics achievement, yet it also demonstrated indirect associations through achievement goals and grit. Specifically, it was positively linked to achievement via mastery-approach, mastery-avoidance, and performance-approach goals, as well as directly through grit, whereas a negative indirect association emerged through performance-avoidance goals. Furthermore, a growth mindset exhibited positive sequential indirect relationships through multiple pathways: it positively influenced achievement via mastery and performance-approach goals, which in turn supported grit; notably, it also contributed positively through a pathway in which it was negatively associated with performance-avoidance goals, which themselves were negatively related to grit, with grit ultimately correlating positively with mathematics achievement.</p> Conclusion <p>The relationship between a growth mindset and mathematics achievement is primarily indirect, operating through a chain of motivational and behavioral mediators. Although a direct negative correlation was observed, growth mindset demonstrated positive sequential indirect associations with achievement via achievement goals and grit. These findings support a sequential motivational model in which mindset shapes motivational processes, which in turn drive goal-directed behaviors to produce outcomes. They also suggest that interventions targeting both adaptive goal-setting and the cultivation of grit may be more effective in promoting academic development than those focusing solely on mindset.</p>