Human Immunodeficiency Virus (HIV) testing services are known as the primary step in preventing the spread of HIV. However, access to these crucial services varies across regions within continents due to disparities in healthcare infrastructure, resources, and awareness. Approximately one in every five people living with HIV (PLWH) encounters obstacles in accessing HIV testing, notably in Eastern and Southern Africa, where geographical, resource, awareness, and infrastructure limitations prevail. Consequently, HIV remains a significant public health concern in these regions, necessitating expanded testing efforts to combat the HIV/AIDS disaster. Despite these challenges, there is a lack of scientific evidence on the prevalence of HIV testing and its determining factors in Rwanda. This study determined the prevalence of never being tested for HIV and its associated factors among sexually active individuals aged 15-56 who participated in the Rwanda AIDS Indicators and HIV Incidence Survey (RAIHIS). This cross-sectional study enrolled 1846 participants. The variables were extracted from the RAIHIS dataset and statistically analyzed using STATA software version 13. Bivariate and multivariate logistic regression models were employed to identify predictors of never having undergone HIV testing, with a 95% confidence interval and a 5% statistical significance level applied. The prevalence of non-testing for HIV was 17.37%. Being aged 15-30 years (aOR 2.57, 95%CI 1.49-4.43, p < 0.001) and male (aOR 2.44, 95%CI 1.77-3.36, p < 0.001) was associated with an increase in the odds of never testing for HIV. Further, those from urban area were less likely than those living in rural areas to have never tested for HIV (aOR 0.31; 95% CI 0.38-0.67; p < 0.001). Participants who were not aware of HIV test facilitates were more likely to have never undergone HIV testing (aOR 1.75; 95% CI 1.25-2.47; p = 0.031) than their counterparts. While the prevalence of HIV non-testing remains modest, the significance of youth, male gender, lack of awareness, and rural residence as influential factors prompts a call for inventive strategies to tackle the reasons behind never having undergone HIV testing. Further exploration using mixed methodologies is advocated to better comprehend socio-cultural impacts and causation relating to these identified factors.