This study examines the impact of internal control effectiveness on the efficiency of electronic operating systems in public-sector institutions, based on the COSO framework. It analyzes how key control components - control environment, risk assessment, control activities, information and communication, and monitoring - interact with digital systems such as ERP, HRMS, and financial information systems. A descriptive-analytical design was applied using a stratified random sample of staff from the College of Science at the University of Diyala, Iraq. Data were collected through a structured questionnaire measuring internal control availability, system usage, and perceived system efficiency. Reliability testing confirmed strong internal consistency (Cronbach’s α = 0.89). Statistical analysis, including Pearson correlation and simple linear regression, revealed a significant positive relationship between internal control and system performance. The results show that internal control explains 55% of the variance in system efficiency (R² = 0.55; β = 0.62; p < 0.001). Findings indicate that higher levels of internal control are associated with improved efficiency, reliability, and compliance in electronic systems. The study concludes that integrating internal control mechanisms into system design, alongside staff training and the use of e-audit tools such as audit trails and role-based access control, is essential for strengthening the performance of electronic operations in public institutions.