The aim of this research was to establish the effect of a social problem-solving training program for 8th grade students. In the experimental group, 14 students were 14 years old and 1 student was 15 years old. In the control group, 13 students were 14 years old and 2 students were 15 years old. The Aggression Questionnaire (AQ) was administered to the students. The students in the experimental group were trained in the Social Problem-Solving program at school. The students in the Social Problem-Solving Training Program had statistically significant lower scores on physical aggression, anger, hostility, indirect aggression and total aggression than the students who did not undertake the program.