This study evaluates the short-term effects of a remedial education program that provided additional instruction to underperforming high school students in Israel. The intervention prepared students for the matriculation exams. Using a comparison group of schools that enrolled in the program later and implementing a difference-in-differences estimation strategy, we found that the program raised the school mean matriculation rate by 3.3 percentage points. This gain reflects an effect on targeted participants and the absence of externalities on their untreated peers. The program was found to be less cost effective than two alternative interventions based on incentives for teachers and students.