ABSTRACTBackground: Academic procrastination is common among university students and its effect on their achievement is worrisome. Although procrastination is often depicted as self-regulation failure, research still needs to examine the self-regulatory mechanisms involved in the relationship between procrastination and achievement.Objectives: In this prospective study, we sought to (a) unravel the unique effect of academic procrastination on university grades, (b) examine the mediating role of task-oriented and disengagement-oriented coping as a self-regulatory pathway toward achievement, (c) control for the potential confounding influence of past achievement and working memory capacity.Methods: A sample of 258 university students completed self-report measures of academic procrastination and coping, and performed tests of working memory. Their semester grade point average was collected at the end of the semester.Results: Results of structural equation modeling showed that academic procrastination negatively predicted subsequent academic achievement, even after controlling for high school achievement and working memory capacity. Furthermore, indirect effects revealed that task- and disengagement-oriented coping explained 70% of the total effect.Conclusion: These findings outline that the effect of academic procrastination cannot be reduced to a history of academic difficulties or limited cognitive ability and that coping plays an important role in the procrastination – achievement relationship.