This study investigated the relationship between leadership styles and business sustainability of small and medium enterprises (SMEs) in Nakawa Division, Kampala District, Uganda. Leadership had been widely recognized as a pivotal determinant of organizational outcomes, yet its specific effects on the sustainability of SMEs in Uganda's urban business environment had received limited scholarly attention. The study examined three dominant leadership styles transformational leadership, transactional leadership, and servant leadership and their effects on the economic, social, and environmental sustainability dimensions of SMEs. A cross-sectional survey of 306 SME owners, managers, and senior employees in Nakawa Division was conducted, and multiple regression analysis was used to test the relationships of interest. The findings revealed that leadership styles had a statistically significant positive effect on business sustainability, collectively explaining 57.3% of the variance in sustainability outcomes. Transformational leadership emerged as the strongest predictor of sustainability, followed by servant leadership and transactional leadership. The study offered important theoretical contributions and practical recommendations for SME leaders, business support organizations, and policymakers in Uganda.