Background <p>Improving the oral health of elderly individuals, involving various healthcare providers, should be a key objective for multidisciplinary teams responsible for their care. We aimed to compare the effectiveness of an oral health education program based on the health action process approach (HAPA) model when provided by a dentist versus a health officer among elderly people.</p> Methods <p>This cluster-randomized controlled trial included elderly residents aged more than 60 years from 24 municipal neighborhood houses (<i>n</i> = 190) in Tehran, Iran, in 2021. A questionnaire was administered through face-to-face interviews at baseline to collect sociodemographic characteristics and HAPA model constructs related to toothbrushing behavior. The Simplified Oral Hygiene Index (OHI-S) was also assessed. The neighborhood houses were assigned to two groups via simple randomization: Group A, which received oral and dental health education based on the HAPA model by a dentist and an educational pamphlet (<i>N</i> = 89); and Group B, which was educated by a health officer and an educational pamphlet (<i>N</i> = 101). Both groups received reinforcement every two weeks. Follow-up oral examinations were conducted after 1 and 3 months by a blinded, calibrated examiner. The marginal model of generalized estimating equations (GEEs) with Bonferroni post hoc correction was used for intragroup and intergroup comparisons.</p> Results <p>The frequency of toothbrushing was not significantly different between the two groups (<i>p</i> = 0.09) after one or three months. However, the frequency of toothbrushing increased significantly in both groups (<i>p</i> &lt; 0.001). Additionally, no difference was found in the OHI-S score between the two groups (<i>p</i> = 0.56); nevertheless, there was a statistically significant improvement in oral hygiene status in both intervention groups (<i>p</i> &lt; 0.001).</p> Conclusion <p>No difference was observed in the effectiveness of educational interventions using the HAPA model when delivered by a dentist versus a health officer working in a municipal center. Both interventions were effective at promoting the oral hygiene status of elderly individuals. These interventions could be integrated into existing public health programs.</p> Trial registration <p>The trial protocol was registered in the Iranian Registry of Clinical Trials (IRCT) on 7-12-2020 (registration number: IRCT20200928048868N1).</p>