This study investigates the relationship between management accounting practices and financial performance among small and medium-sized enterprises (SMEs) in Rivers State, Nigeria. The study adopts a descriptive research design to identify the relationship between the variables under investigation. The population consists of 74 SMEs registered with the Port Harcourt Chamber of Commerce, with a scientifically determined sample size of 63 firms, selected through convenience sampling. Primary data were obtained using structured questionnaires administered to management accountants, budget officers, and finance managers, while secondary data were sourced from corporate records of the Corporate Affairs Commission, Federal Inland Revenue Services, and private accounting firms. The analysis employed both parametric and non-parametric statistical techniques, with multiple regression analysis as the primary tool to examine the relationship between management accounting practices, specifically activity-based costing (ABC) and budgeting (BGT), and financial performance indicators, namely return on assets (ROA) and return on equity (ROE). The models specified for the study tested the impact of ABC and BGT on ROA and ROE, respectively. Reliability and validity of the research instruments were ensured through expert reviews and the computation of Cronbach's alpha. The findings revealed a significant positive relationship between management accounting practices and financial performance among SMEs in Rivers State. Both activity-based costing and budgeting were found to enhance operational efficiency, resource allocation, and financial performance. The study concludes that adopting advanced management accounting practices is crucial for improving the financial performance of SMEs. It recommends that SMEs' management should prioritize the adoption of robust accounting techniques and provide necessary training to enhance decision-making and operational success.