In this study, the effect of a social skills-based psychoeducation programme, consisting of eight sessions, on primary school students’ social skill levels was investigated. The study group of the research consisted of a total of 24 third and fourth grade students attending a state primary school. In the research, a quasi-experimental model with a control group and pretest, posttest and follow-up test was used. A Social Skills Knowledge Test, Sociometric Technique and Personal Information Form were used for data collection. After the pretest measurement, the Social Skills-Based Psychoeducation Programme was implemented by the researcher for the students in the experimental group between May and June 2019, for two days per week (4 weeks, 8 days) and approximately 45 minutes per day. No group sessions or activities were conducted with the control group, and only the pretest and posttest were administered to those students.The posttest measurements were taken one week after the end of the sessions, and the follow-up measurements were made six months later. The Wilcoxon signed-ranktest and Mann-Whitney U test were used for the analysis of the obtained data. As a result of the study, it was observed that the social skill scores of the students in the experimental group increased significantly compared to those of the students in the control group. At the same time, the follow-up test was applied to the students in the experimental group six months later, and it was observed that the difference between the posttest and follow-up test mean scores was not significant and that the effect of the social skills-based psychoeducation programme was still continuing. The findings obtained reveal that the social skills-based psychoeducation programme was effective in improving students’ social skills.