This study examined the relationship between inventory management practices and the operational performance of retail supermarkets in Kampala Central Division, Uganda. Inventory is typically the largest current asset of a retail supermarket, and its management directly shapes costs, product availability, and customer satisfaction. The study investigated how inventory control systems, demand forecasting, stock replenishment, and warehouse management relate to operational performance. A cross-sectional survey design with a mixed-methods approach was adopted, and data were collected from 160 respondents comprising supermarket managers, procurement officers, and store staff using structured questionnaires and interviews. Descriptive statistics, Pearson correlation, and regression-based path analysis were used. The results revealed a strong positive and significant relationship between inventory management practices and operational performance (r = 0.67, p < 0.01), with the practices jointly explaining 65.0% of the variance in operational performance (R² = 0.650). Inventory control systems and demand forecasting emerged as the strongest predictors. The study concludes that sound inventory management practices significantly enhance operational performance and recommends investment in inventory control systems, improved demand forecasting, and efficient replenishment.