Abstract: The principle of subsidiarity is increasingly important in strengthening employee participation, delegated authority, and responsiveness in organisational decision-making. However, effective application of subsidiarity may be constrained by the need to balance staff autonomy with managerial oversight. This study examined the influence of subsidiarity on decision-making at the Children of God Relief Institute in Kitui County, Kenya. The study was anchored on Participative Leadership Theory and Institutional Theory. A mixed-methods approach and convergent parallel design were adopted. The study targeted 172 participants using census and purposive sampling. Questionnaires were administered to 165 employees and caregivers, with 157 responding, while seven managers were interviewed. Quantitative data were analysed using SPSS version 25 through descriptive and inferential statistics, while qualitative data were thematically analysed. Subsidiarity was generally practisedat COGRI, with a composite mean of 3.68 (SD = 0.99). A strong positive and statistically significant relationship existed between subsidiarity and decision-making (r = .734, p < .001). Regression analysis showed that subsidiarity significantly predicted decision-making (β = .734, p < .001) and explained 53.9% of the variance (R² = .539). Qualitative findings indicated that staff were generally empowered to make routine decisions within their responsibilities, while complex and resource-intensive decisions required management approval. The study concludes that effective delegation of authority and staff autonomy contributes to responsive decision-making. The study recommends strengthening delegation guidelines, staff participation, and appropriate managerial oversight at COGRI.