Objective. This research investigates education based on the trans-theoretical model (TTM) on sexual function of married women in Iran. Patients and Methods. This study was quasi-experimental. In this study random allocation was not used. This study included 200 Iranian married women -20 to 50 years old -from 20 health centres in Iran from 2020 to 2021. Using questionnaires, the demographic, trans-theoretical model (TTM) constructs were measured and analysed. Each group met for 60 minutes, twice weekly, for 12 weeks. Six months were set aside for completion of the survey (pre-intervention and post-intervention). The proceeding analyses were conducted using SPSS (version 20) statistical software package. Results. The average rates of TTM constructs (stages of Change (6.355 ± 1.342), processes of change (8.614 ± 3.406), self-efficacy (22.447 ± 6.783), decisional balance (5.355 ± 2.342) and sexual function (32.37 ± 4.73) in education group was increased meaningfully (P-value < 0.05); these changes were not meaningful in control group (P-value > 0.05). Conclusions. The findings of this study based on TTM, could be a good guideline for designing interventions in women sex education program, also could be used to prepare stability of women to continue appropriate sex education from return to previous habits. The results of this research suggest that the use of TTM can be used in educational interventions on sexual function of married women in Iran and have useful results.