This study examines the impact of ISO 9001 on operational efficiency in Micro, Small and Medium Enterprises (MSMEs). ISO 9001 is the internationally recognized standard for quality management systems, and it is designed to help organizations establish consistent processes, improve quality, strengthen decision-making, and promote continual improvement. For MSMEs, these features are especially important because smaller firms often face operational issues such as process inconsistency, higher defect rates, weak documentation, and inefficient resource utilization. The study uses secondary data from official ISO material and published research on manufacturing MSMEs in India. The analysis shows that effective ISO 9001 implementation improves process standardization, customer satisfaction, prevention of non-conformities, cost control, supply-chain and delivery performance, and overall sustainable operational performance. The paper concludes that ISO 9001 can significantly improve operational efficiency in MSMEs when it is implemented as a genuine management system rather than as a symbolic certification exercise.