The purpose of this study is to better understand the implications for using self-reported grade point average (GPA) versus school-record GPA in academic achievement research. First, we found that nearly half the youths interviewed overreported their GPAs by at least 2 half grades. Second, youth who overreported their GPAs also reported less psychological distress, more successful academic beliefs, and fewer problem behaviors. Third, we found that self-reported GPA was associated with all 3 sets of variables, but school-record GPA was associated with only problem behaviors. The findings suggest that it may be useful for researchers to consider how different measures of GPA may influence their results.