The purpose of the present study is investigating the effect of educational intervention based on health belief model (HBM) on oral cancer prevention in smoker men. This is a quasi-experimental study carried out on 200 smoker men with the age of 40 or older (100 subjects for the experimental group and 100 subjects for control group) resident in Fasa City, Fars Province, Iran, in 2017-2018. The educational intervention for the experimental group included seven educational sessions for 50 or 55 min-based HBM. A questionnaire consisted of items about demographic information, knowledge, HBM constructs (perceived susceptibility, severity, benefits, barriers, self-efficacy, and cues to action) was used to measure the oral cancer prevention before and 6 months after the intervention. The mean age of the men was 51.35±8.41 years in the experimental group and 52.28±8.09 years in the control group. Based on the obtained results, significant enhancement is observed in average scores of knowledge, perceived susceptibility, severity, benefits, self-efficacy, cues to action, and oral cancer prevention behaviors in experimental group; however, no significant changes are observed in average scores of knowledge, perceived susceptibility, severity, benefits, self-efficacy, cues to action, and oral cancer prevention behaviors of control group. Also, results indicated that, the educational program based on HBM model have positive effect on oral cancer prevention with the improvement of subject's knowledge, perceived susceptibility, severity, benefits, and self-efficacy.