<p>This study investigated the effect of friendship ties education (FTE) on primary school students’ psychological well-being and peer relationships. We conducted the research using one of the quantitative research designs, the experimental design. The research study group consisted of 94 third-grade students enrolled in primary school who were divided into experimental, placebo, and control groups. This study was conducted with students in Istanbul in the spring semester of the 2021–2022 academic year. In the study, we applied FTE to the experimental group, applied cooperative learning (CL) to the placebo group, and did not apply any educational activity to the control group. We gathered the research data using a scale of psychological well-being and peer relationships. We analyzed the data obtained through the scales with the t-test and ANOVA included in the SPSS package program. According to the findings, the experimental group’s psychological well-being and peer relations scores were significantly higher than those of the control and placebo groups following activities. In addition, the placebo group students scored considerably higher than the control group regarding psychological well-being and peer relationships. The findings demonstrate the significance of FTE and CL for developing psychological well-being and peer relationships.</p>