Background <p>Comprehensive HIV/AIDS knowledge is essential for prevention, yet older adults-particularly men aged 50–59 years-remain underrepresented in HIV research and programming across sub-Saharan Africa. Despite Rwanda’s strong HIV response, limited evidence exists on HIV knowledge among older men. This study assessed the prevalence and determinants of comprehensive HIV/AIDS knowledge among Rwandan men aged 50–59 years. The analysis was guided by a conceptual framework incorporating predisposing, enabling, and contextual factors that shape HIV knowledge among older men.</p> Methods <p>This cross-sectional study used data from the 2019–20 Rwanda Demographic and Health Survey (RDHS), analyzing a weighted sample of 665 men aged 50–59 years. Comprehensive HIV knowledge was defined using six standard DHS indicators. Weighted descriptive statistics, bivariable analyses, and multivariable logistic regression were conducted to identify associated factors, adjusting for the survey design. Results are presented as adjusted odds ratios (AORs) with 95% confidence intervals (CIs).</p> Results <p>Overall, 69.9% (95% CI: 66.2–73.4%) of men aged 50–59 years demonstrated comprehensive HIV/AIDS knowledge. In adjusted analyses, having secondary education (AOR = 3.18; 95% CI: 1.31–7.75) and health insurance coverage (AOR = 1.71; 95% CI: 1.07–2.73) were significantly associated with higher odds of comprehensive knowledge. Other factors, including mobile phone ownership and internet use, were not significant after adjustment.</p> Conclusions <p>Comprehensive HIV knowledge among Rwandan men aged 50–59 years remains below global prevention targets. Education and health insurance coverage were the most important enabling factors, consistent with the study’s conceptual framework. Integrating HIV education into aging-friendly and insurance-linked health services may strengthen awareness and support Rwanda’s continued progress toward HIV prevention goals.</p>