The study aims at investigating 'The Impact of Performance-Based Assessment Strategies on Students' Achievement and Self-Efficacy' in Jordan. In order to achieve that goal, a performance-based assessment strategy has been applied to 72 students in Al-Zarqa city representing a sample of 35 students in which the performance-based assessment strategy was applied to evaluate students' performance assignments, and 37 students who were evaluated in the more traditional manner. The study took 8 weeks, 5 hours per week. An academic final test and self-efficacy measure were applied after the completion of the study. The findings of the study have proved a statistical significance between the mathematical averages on the outcome test and the measure of overall self-efficacy and each of its dimensions in favour of the experimental group.