This study investigates the effectiveness of leadership competencies in relation to team performance and project success within civil society organizations operating in Şanlıurfa, Turkey. Located near the Syrian border, Şanlıurfa plays a critical role in humanitarian response due to its large refugee population. A mixedmethods research design was adopted. The quantitative phase involved structured surveys administered to 300 staff members (including managers, officers, and field workers) in both local and international NGOs. The qualitative phase consisted of two focus group discussions with senior managers to gain deeper insights. The study focused on three main constructs: leadership competencies, team performance, and project success. Statistical analyses using SPSS included descriptive statistics, reliability testing via Cronbach’s Alpha, Pearson correlation, and linear regression. The analysis demonstrated strong internal reliability across scales (α = 0.81 to 0.88). Regression results showed that leadership competencies significantly predict project success (R² = 0.62, p < 0.01) and team performance (R² = 0.59, p < 0.01). Qualitative findings reinforced these results, highlighting emotional intelligence, participative decisionmaking, and adaptability as key leadership traits in humanitarian contexts. This study seeks to address a critical gap in the literature on humanitarian project management by linking leadership competencies with organizational outcomes. It offers both theoretical contributions and practical recommendations, emphasizing the importance of targeted leadership training and culturally competent management to enhance the effectiveness, efficiency, and sustainability of humanitarian interventions in complex field environments.