The study examined the effect of transaction processing systems on financial reporting in Trinity College, Nabbingo, Wakiso District. The research adopted a case study design employing both quantitative and qualitative approaches to investigate how transaction processing systems influenced the accuracy, timeliness, and reliability of financial reports. Data were collected from 152 respondents, including accounting staff, administrators, auditors, and management personnel at Trinity College. The study utilized questionnaires, interview guides, and document analysis as primary data collection instruments. Results revealed a significant positive relationship between transaction processing systems and financial reporting quality (r = 0.798, p < 0.001). The findings indicated that 82.9% of respondents reported improved accuracy in financial reports following the implementation of transaction processing systems, while 78.3% noted enhanced timeliness in report generation. The study found that automated transaction processing reduced error rates by 73.6% compared to manual systems, and financial report preparation time decreased from an average of 15.4 days to 3.7 days, representing a 76.0% improvement in efficiency. Additionally, the research established that 85.5% of respondents confirmed that transaction processing systems enhanced compliance with financial reporting standards and facilitated better audit trails. The study concluded that transaction processing systems significantly improved financial reporting outcomes in Trinity College through automation, real-time data processing, enhanced data integrity, and streamlined reporting processes. Recommendations included continuous system upgrades to maintain technological relevance, comprehensive staff training on system functionalities, regular system audits to ensure data security, and integration of advanced analytical tools to enhance decision-making capabilities based on financial reports generated through transaction processing systems.