The library is an organization that continues to grow and develop along with the behavior of its users. Users who will continue to use the library despite the emergence of many other sources of information, such as the internet, are needed for library sustainability. This study aims to determine the relationship between service quality and satisfaction on user loyalty in-state college libraries in Surabaya, Indonesia. The research method used is quantitative by distributing questionnaires through Google form to 500 respondents of state academic library users with the criteria of having used services in the library. The analysis technique is Confirmatory Factor Analysis (CFA) with the aim of testing the model. Data processing software used is SPSS and Smart PLS. The results of the study are as follows: 1) Service quality has a significant effect on user satisfaction, with a contribution of 79.6%; 2) Service quality has a significant effect on user loyalty, with a contribution of 60.7%; 3) User satisfaction has a significant effect on loyalty, with a contribution of 23.8%; 4) Service quality has a significant effect on loyalty by mediating user satisfaction with a contribution of 19%.