The government of Uganda and its implementing partners have made significant investments in HIV self-testing (HST) services to reduce clinic-related barriers to HIV testing. However, although HSTs have been around for a reasonable time, their uptake, especially among unskilled working individuals, has remained suboptimal, which threatens the efforts to achieve the 95-95-95 UNAIDS goals to end HIV by 2030. This study set out to examine whether knowledge and individual beliefs about self-testing influence the use of HIV self-tests among causal workers in Kampala. This cross-sectional study was conducted among 453 participants selected via systematic random sampling from Darling Uganda Ltd. in Wakiso district between July and September 2023. Standardized questionnaires were used, and the analysis was performed using Pearson Correlations and Linear Regression in SPSS. The findings indicate that HIV self-testing (HST) knowledge was positively related to HST use (r = .387, p≤.01), perceived susceptibility (r = .212, p≤.01), perceived benefits (r = .152, p≤.01), and perceived barriers (r = .101, p≤.05). Individual beliefs, that is, perceived susceptibility (r = .355, p≤.01), perceived benefits (r = .487, p≤.01), and perceived barriers (r = .148, p≤.01), were significantly related to HST use. Perceived benefits were the best predictor of HST use among this population ( β = .442, p = .000). Therefore, (44.2%) of HST use was attributed to the benefits attached to the service. Therefore, increasing awareness regarding the benefits of HST among such populations increases the chances of HIV testing, particularly among men. This can pave the way for the 95-95-95 goal by 2030 of UNAIDS.