Objective:Oral health of pregnant women is very important because of the adverse effects of pregnancy on the oral hard and soft tissues and vice versa. The aim of this study was to evaluate the effect of education on oral health behaviors of pregnant women based on the theory of planned behavior in Birjand.Materials and Methods:This quasi-experimental study was carried out among 150 pregnant women admitted to health centers, who were selected using simple sampling (75 females in each case and control group). Educational program through face-to-face training was performed in the case group, and the control group received only usual training through leaflet distribution. Data were collected using a questionnaire and analyzed by the Statistical Package for the Social Sciences version 18 software at 0.05 significance level.Results:The most frequent age group was 26–30 years. Before the intervention, the mean scores of knowledge, attitude, perceived behavioral control, subjective norms, behavioral intention, and performance of the intervention and control groups showed no significant difference (P ≥ 0.05). After the intervention, the average of all scores in the intervention group showed significant increase compared to the control group (P ≤ 0.05).Conclusion:Face-to-face training using the theory of planned behavior has positive impact on oral health behaviors of pregnant women. Accordingly, training sessions in order to raising awareness and positive attitude and controlling healthcare behaviors can improve oral health behaviors of pregnant women.