Although extensive research has explored the antecedents of academic procrastination, the role of self-regulatory traits, such as grit, has received comparatively less attention. Additionally, the classroom environment and self-regulatory traits may have joint effects on academic procrastination, but this question has not been adequately researched. Addressing these gaps, the present study examines how classroom goal structures and students' grit predict procrastination in mathematics learning, utilizing a sample of 915 primary school students in China. The findings reveal that grit mediates the relationship between classroom goal structures and procrastination. Specifically, classroom mastery goal structure was positively related to grit and further negatively predicted procrastination tendencies. The results also highlight the maladaptive role of performance goal structure, as it was negatively linked with students' consistency of interest and predicted a higher risk of mathematics procrastination. The results extend our understanding of the underlying relationships between classroom climate, self-regulatory traits, and procrastination. The potential reasons for and implications of the findings are discussed.