Background <p>Many countries have introduced health insurance schemes to accelerate progress toward Universal Health Coverage (UHC) and improve access to healthcare. However, limited awareness of catastrophic health expenditures and the risk of impoverishment from healthcare costs may hinder enrollment. In Tanzania, these gaps underscore the importance of financial health risk protection education as a strategy to enhance insurance knowledge and enrollment willingness, especially among rural households.</p> Objective <p>To measure the effect of financial health risk protection education on knowledge and willingness to enroll in health insurance among rural households in Tanzania.</p> Methods <p>The study was a cluster-randomized controlled trial. Total of 560 household heads were assigned randomly to a control or intervention group (280 in each group). A questionnaire was used to collect data. Intervention group received education for 1 month then was followed for 2 months. Outcomes measured were change in knowledge on financial health risk protection, health insurance for all and willingness to enroll. Logistic regression was conducted to establish a relationship between knowledge and willingness to enroll.</p> Results <p>The odds of knowledge about financial health risk protection and health insurance for all increased substantially in the intervention households at endline compared to baseline. Participants in the intervention group were two times more likely to have adequate knowledge about financial health risk protection at the endline compared to the baseline study [(OR = 0.478, <i>p</i> = 0.005) baseline to (OR = 2.3, <i>p</i> &lt; 0.0001) endline]. Similarly, participants in the intervention group were more likely to have adequate knowledge about health insurance at the endline compared to the baseline study [(OR = 0.20, <i>p</i> = 0.29) baseline to (OR = 1.4, <i>p</i> &lt; 0.0001) endline]. The odds of willingness to enroll in health insurance increased two times more in the intervention households at the endline compared to the baseline study [(OR=-0.28, <i>p</i> = 0.18) baseline to (AOR = 2.2, <i>p</i> &lt; 0.0001) endline].</p> Conclusion <p>Financial health risk protection education significantly improved knowledge and willingness to enroll in health insurance among rural households, demonstrating its potential to promote insurance uptake. Scaling up such educational interventions in rural Tanzania is recommended to address knowledge gaps, enhance enrollment, and advance progress toward Universal Health Coverage.</p> Trial registration <p>The trial was registered on 11th April 2023, with registry number PACTR202304503715724, Clinical trial number not applicable.</p>