Background: Dental caries is considered a major global health issue and among the most challenging diseases worldwide. An effective way of preventing dental caries is the fissure sealant (FS) therapy. Objective: To determine the effectiveness of an educational intervention developed based on the health belief model (HBM) for parents’ perception of FS therapy for their children. Methods: Quasi-experiment among 300 parents of 6-12 year-old children, 150 in the intervention group (IG) and 150 in the control (CG), in the south of Iran recruited via both clustering and convenience sampling. Data were collected using a validated questionnaire collecting demographic information, knowledge and data on HBM constructs and FS behaviour. Eight intervention sessions, 40-60 minutes long, were held for over month. The primary outcome was child’s receipt of fissure sealants 3 months after the intervention. Results: The two groups had similar knowledge and the HBM constructs at baseline. After the intervention, the receipt of FS therapy was 65% and 12% in the IG and CG, respectively (p < 0.001, Chi Sq.). ANCOVA supported post-test differences between the intervention and control groups when accounting for baseline scores (p<0.05). Conclusions: The educational HBM-based intervention improved parents’ perceptions and their children’s receipt of FS therapy. The intervention affected the HBM constructs. Barriers to healthy oral/dental behaviours may be reduced by interventions at multiple layers (beyond the individual level). Keywords: Dental caries, Health Belief Model, Fissure Sealant Therapy