BackgroundPremenstrual syndrome (PMS) is a prevalent health issue impacting women, significantly impacting their well-being and fostering a negative attitude of femininity and menstruation. We investigated the effect of group counseling based on positive psychology on the severity of PMS symptoms.MethodsParticipants in the intervention group engaged in six online sessions of group counseling focused on positive psychology via WhatsApp. Data were collected using the Premenstrual Symptoms Screening Questionnaire (PSST) before, immediately, and two months post-intervention. Analytical assessments were performed using SPSS 16 software using Chi-square, independent t-tests, and repeated measures analysis of variance (ANOVA). Comparative analyses were carried out using the Bonferroni post hoc test with a 95% confidence level.ResultsThe mean intensity of PMS symptoms in the intervention group significantly decreased from 21.60 (2.50) to 13.35 (4.727) and 14.750 (5.963) immediately and two months after the intervention; however, the difference was not significant in the control group. The results of repeated measures ANOVA showed that the effect of the intervention over time and the interaction between time and group were significant. The Eta effect size was about 0.20 and 16%, respectively (p = 0.001). According to Bonferroni post hoc test results, the difference in the mean scores of the severity of PMS symptoms before the intervention was statistically significant compared to both follow-up periods (p ≤ 0.007). However, the difference in mean scores immediately after the intervention compared to two months after the intervention was not statistically significant (p = 0.42).ConclusionUsing a positive counseling approach demonstrates efficacy in alleviating the severity of PMS symptoms in the short term. While all women can benefit from such interventions, targeting adolescents is particularly strategic, as early interventions can foster positive attitudes toward menstruation. Additionally, social media platforms like WhatsApp provide a feasible and engaging medium for adolescent health interventions. Integrating this approach into adolescent health promotion package appears to be a viable measure worthy of consideration by relevant policymakers.Trial registrationCurrent Controlled Trials IRCT20201113049377N1, Date of Registration 2020, 12, 08.