Education is key to behavioural adoption and acceptability of health interventions. We evaluated the impact of an educational intervention administered 1:1 to individuals incarcerated in four Canadian federal prisons on COVID-19 vaccine uptake. Eligible individuals (those who had refused all COVID-19 vaccines) were randomized 2:1 to receive the educational intervention or not (control group); those who received the intervention completed questionnaires assessing COVID-19 vaccine-related knowledge, attitudes, and beliefs pre- and post-educational intervention. The primary and secondary outcome measures were COVID-19 vaccine uptake and vaccine confidence, respectively. Between May 3 and September 9, 2022, 202 participants were randomized to receive the intervention, of whom 127 (63 %) agreed to participate. Participants who were randomized to the intervention had higher COVID-19 vaccine uptake vs. the control group (5 % vs 1 %, p = 0.046). COVID-19 vaccine-related knowledge, attitudes, and beliefs improved post-intervention. Education increases COVID-19 vaccine uptake and confidence among people in Canadian federal correctional facilities.