Purpose: Women with epilepsy (WWE) frequently experience sexual problems, including sexual dysfunction and sexual distress. Therefore, this study aimed to examine the efficacy of a mindfulness-based cognitive therapy for sexuality (MBCT-S) on sexual function and intimacy among older adult WWE in Iran. Methods: A multicenter randomized controlled trial was conducted at 15 neurology clinics in three Iranian cities. WWE together with their partners and healthcare providers were randomly assigned in patient and partner (PP; n = 220), patient, partner, and healthcare provider (PPHP; n = 220), or treatment as usual (TAU; n = 220) group. WWE and their partners in both the PP and PPHP groups received eight weeks of MBCT-S sessions. In the PPHP group, three individual sessions on sexual counseling were added for healthcare providers. Self-assessment scales were used at baseline, one month and six months after completing the intervention. Mixed linear regression models were developed to determine differences among the three groups. Multilevel mediation analyses were conducted to understand the mediating effects of mindfulness, intimacy, patient-physicians relationship and sexual counseling barriers. Results: Improvements in sexual function, sexual distress, and intimacy were found in both the PP and PPHP groups at one-month and six-month follow-ups. The PPHP group compared with the PP group had greater improvement in intimacy at both follow-ups. Regarding sexual function, the PPHP group performed better than the PP group at the six-month follow-up. Conclusions: The MBCT-S appears efficacious in enhancing sexual function and reducing sex-related distress in Iranian older adult WWE. Future studies should examine its efficacy in other populations.