This study investigated the effect of mobile banking services on the financial performance of commercial banks in Uganda, using Centenary Bank, Kampala Branch, as a case study. The rapid adoption of mobile technology has transformed banking service delivery, and this study sought to determine how mobile banking dimensions— transaction volume, service accessibility, cost efficiency, and customer adoption—affect key financial performance indicators such as return on assets, net income, and cost-to-income ratio. A descriptive and explanatory research design was adopted, and data were collected from 120 respondents comprising bank staff and customers using structured questionnaires, supplemented by secondary financial data. Descriptive statistics, Pearson correlation, and multiple regression were used for analysis. The findings revealed a strong positive and significant relationship between mobile banking services and financial performance (r = 0.68, p < 0.01), with mobile banking explaining 52.3% of the variance in financial performance (R² = 0.523). Transaction volume and cost efficiency were the strongest predictors. The study concludes that mobile banking significantly enhances bank profitability and operational efficiency and recommends continued investment in mobile platforms, cybersecurity, and customer financial literacy.