This research studied the self-efficacy beliefs of 107 seventh-grade mathematics students, particularly focusing on the accuracy and predictability of their beliefs. Path analysis showed that calibration accuracy had both direct and indirect effects on math performance, with indirect effects mediated through self-efficacy beliefs. Self-efficacy played a direct role in predicting students' math performance, postperformance self-evaluation, and postperformance judgments of effort. The effects of prior math achievement on math performance were mediated largely through the students' self-efficacy beliefs. The findings also did not reveal any gender differences in self-efficacy or calibration. Although the findings supported self-efficacy predictions, they also suggested important issues for future research, including accuracy of self-efficacy training in math problem solving and assessment of effort judgments prior and post performance.