Background: Premenstrual syndrome (PMS) is one of the most widespread menstrual disorders in women of reproductive age. This recurrent syndrome is a combination of physically, mentally, or behaviorally disturbing changes occurring during the secretory phase of the menstrual cycle. The aim of this study is to determine the effect of a cognitive-behavioral therapy-based educational intervention using social networks on PMS in female health center employees in Rudbar, Iran. Methods/design: A randomized superiority controlled trial will be conducted involving 140 female employees of health centers affiliated with the Guilan University of Medical Sciences, Rudbar. The study involves a block size of 4 and 6 in a randomly varied order, 140 women who meet all the inclusion criteria will be randomly and equally divided into 2 groups: the intervention and the control groups. Those in the former group will receive a cognitive-behavioral therapy-based treatment for eight consecutive weeks on the social network platform WhatsApp; however, those in the control group will not be offered any treatment except usual care practices (unprotocolized usual care). The study’s primary outcome is the severity of PMS symptoms, and the secondary outcomes include general self-efficacy, work-related quality of life, the impact of PMS on daily life, coping with the symptoms, and experiencing anxiety and depression at the beginning of the study to identify people with PMS. A daily record of the symptoms will be completed for two consecutive months by all female employees aged 20–45 years who wish to participate in the study. According to the initial screening, those with moderate to severe PMS will be included. We will use the MLwin software for the analyses. All questionnaires will be completed by both groups immediately and 8 weeks after the termination of the treatment. The data will be analyzed using linear mixed-effects modeling with random intercepts and slopes. Discussion: It is anticipated that the findings of the present study may demonstrate the effectiveness of the cognitive behavioral therapy intervention on the severity of PMS symptoms that could guide healthcare providers in opting for suitable treatment alternatives for the syndrome. Ethics and dissemination: The research proposal is approved by the Human Ethics Committee of Qazvin University of Medical Sciences (IR.QUMS.REC.1399.252). The results of this intervention trial will be submitted for publication in a peer-reviewed research journal. Trial registration: Iranian Registry of Clinical Trials IRCT20180218038789N4. Registered prospectively on October 28, 2020