This study assessed the effectiveness of private security organizations (PSOs) in providing security services to commercial entities in Uganda, specifically in the Kampala Metropolitan Police East (KMP East) region. Using the systems theory as a framework, the research focused on four key objectives: (1) the impact of employee capability on service effectiveness, (2) the role of the legal framework in enhancing PSO performance, (3) the influence of technological adoption on the effectiveness of PSOs, and (4) the relationship between customer satisfaction and security service delivery. The study employed a quantitative approach, gathering primary data from a sample of 144 participants, including employees of Saracen Security Ltd and their commercial clients, via questionnaires. A cross-sectional survey and correlation research design were adopted. Data analysis was conducted using SPSS, incorporating frequency distributions, Pearson correlation coefficients, and multiple linear regression. The findings revealed that employee capability and the legal framework were significant predictors of the effectiveness of PSOs in providing institutional security. However, technological adoption and customer satisfaction did not significantly predict security service effectiveness. Notably, the study indicated that 74.3% of the variation in institutional security effectiveness could be explained by the studied variables. The study recommends several measures to improve PSO effectiveness, including policy reviews, ongoing capacity building for security personnel, fostering technological collaborations, enhancing responsiveness and reliability, and focusing on customer satisfaction. Additionally, staff and clients should be oriented on the legal frameworks governing security services. These interventions are vital for improving the performance and sustainability of PSOs in Uganda.