Purpose: Although student evaluation of teaching (SET) is widely used, there has been a significant disparity between its potential benefits with the actual impact on improving educational quality. This study aims to inquire into the factors contributing to this discrepancy and the underlying mechanisms hindering the effective utilisation of SET. Design/methodology/approach: This qualitative case study used problem-based methodology to investigate the theories of action of administrators involved in SET. The study uses SET documents and individual interviews with 18 administrators from six Vietnamese higher education institutions. Findings: While the administrators monitored SET data and addressed SET problems, few used it for quality improvement. The participants' SET approaches were influenced by various constraints, especially the intricate interaction between neoliberal agendas with professional and cultural values. Research limitations/implications: Despite a lack of statistical generalisability, this study contributes to analytical generalisation by vividly portraying the complexity of the SET practice in a higher education context. Practical implications: This study suggests a more inclusive approach to quality improvement that prioritises multi-stakeholder engagement. Social implications: The constraint analysis offers invaluable insights into the challenges and dynamics of SET practice, which can be used to enhance SET effectiveness and overall educational quality. Originality/value: This paper addresses the need to examine the theories of action of administrators involved in SET, emphasising the significance of a comprehensive understanding of the stakeholders' underlying reasoning process for successful evaluation implementation.