Purpose: Library quality assurance systems are collaborative governances that facilitate the presentation of data on international accreditation of departments, which contains data on services, human resources, library facilities and infrastructure. This research analyzes the supporting and inhibiting factors and the advantages of the library quality assurance system in supporting international accreditation of departments at Sebelas Maret University (UNS) Surakarta, Indonesia using Talcott Persons' theory of structural functionalism. Design/methodology/approach: Primary data in exploratory research and action research obtained from the Quality Assurance Team at the university level under the Educational Quality Assurance and Development Institute (LPPMP), the Quality Assurance Unit (UPM) at the faculty level and the Quality Control Group (GKM) at the department, librarian and academic community levels. Supporting informants are international assessor practitioners. Data validation using source triangulation, namely information obtained through different sources, and method triangulation through different methods. Data obtained from library studies, observations, Focus Group Discussions (FGD), documentation and interviews with staff, library leaders, lecturers from departments that have and will carry out international accreditation and UNS students and analyzed interactive analysis models, namely data reduction, data presentation and concluding. Findings: The research results show that the UNS Library quality assurance system facilitates higher education organizations, such as bachelor's, master's and doctoral departments at UNS; search and presentation of international accreditation data. Supporting factors include the availability of digital library systems, online catalogs (UNSLA), e-journal and e-book databases, library websites and library data links for accreditation; facilities and infrastructure consist of indoor-outdoor study rooms; library social media; Self Access Terminal room; facilities for international students; involvement of librarians in international internships/conferences, librarians who have had competency tests and certification; librarians pursuing doctoral degree and support for student interns in system development. Inhibiting factors include the unavailability of programmers and dependence on UNS Information and Communication of Technology Unit. The benefits of the department quality assurance system include accelerating and improving the organization's quality and presentation of international accreditation data for departments at UNS. Originality/value: This type of qualitative research with an exploratory approach takes library study data, observations and in-depth interviews with library staff and quality assurance of departments. The informants were selected using purposive sampling, which was adjusted to the needs and interests of the research. It also uses the action research method, a collaboration between the quality assurance unit, librarians and academics. Action research is a form of collective self-reflection that involves a series of daily activities, which include the processes of research, diagnosis, planning, implementation, monitoring and establishing the necessary relationships between evaluation and self-development. The research object is something that will be subject to conclusions resulting from something that will be discussed in the research. The object of this research is the quality assurance of the UNS Library. Primary data was obtained from the Quality Assurance Team at the university level under the LPPMP, the Quality Assurance Unit (UPM) at the faculty level and the Quality Control Group (GKM) at the department, librarian and academic community levels. Supporting informants are international assessor practitioners. Data will be collected using observation, in-depth interviews, Focus Group Discussion (FGD) and documentation. To ensure the validity of the data, source triangulation is used, namely, information obtained through different sources, as well as method triangulation through different methods, for example, interviews with observation or FGD. Data analysis using an interactive analysis model, namely data reduction, data presentation and concluding. This research was conducted at the UNS Library, with the research object being all departments at Sebelas Maret University, which have and will undergo international accreditation. [ABSTRACT FROM AUTHOR]