This study develops a simplified Library Customer Satisfaction Index (LCSI Lite) for public libraries. Using data collected from questionnaires administered at four public libraries in South Korea, structural equation modeling was used to measure the scores. The suggested model was confirmed to have good acceptable fit, and that three dimensions of service quality (library personnel, library resources and user services, and facilities and equipment) influenced loyalty via customer satisfaction. After successful factor analysis and reliability testing, three items for library personnel, four for library resources and user services, two for facilities and equipment, two for customer satisfaction, and two for loyalty were analyzed. Means of each item in service quality were over 3.77, and those in satisfaction and loyalty were over 4.00. Direct and indirect effects of the dimensions of service quality were analyzed, with the effect of satisfaction on loyalty. LCSI Lite scores for the libraries as a whole (73.90 out of 100) and for each library were calculated using suggested formula. Finally, research and managerial implications, some recommendations and suggestions for further research, limitations, and conclusions were presented.