Trust and certification in research data and theses in institutional repositories are the new concept for Thai university professionals both in the university libraries and the research centers. Even though institutional repositories and research databases are infrastructures of scholarly communication that ensure accessibility of research data and theses which requires policies, standards, and data management plan. This study focuses on how Thai universities handle research data and theses for long-term use, and introducing basic and formal certification in repository assessment methods to the library directors and research center directors in Thai universities. The research objectives are to analyze the factors of research data quality accreditation standards in institutional repositories, and to study the readiness of Thai universities towards research data quality accreditation standards in institutional repositories. A qualitative research method was applied by interviewing 30 library directors and 30 research centers directors in 30 Thai universities with high research productivity level. In-depth interviews were qualitatively analyzed using content analysis. The research findings will identify the status of research data and theses in Thai university libraries and research centers and the readiness level of Thai Universities towards the research data quality accreditation standards in institutional repositories.