Purpose of Study —This paper explores existing literature and expert views to identify the critical success factors (CSFs) for the effective implementation of Lean Sigma (LSS) as Operation Excellence (OPEX) and Continuous Improvement (CI) initiatives in higher education institutions (HEIs). Design/methodology/approach —A comprehensive literature review was conducted to identify the CSFs of Lean Sigma implementation. Second, qualitative research was employed through a semi-structured interview to explore the views of the OPEX experts based on their experience in identifying the CSFs of LSS projects they have implemented in the higher education environment. Finally, a Template Analysis (TA), a form of thematic analysis, was used to establish useful themes and allow the researcher to organise the emerging themes into meaningful groups. Findings —–The expert interviews show considerable consensus with the commonly cited CSFs of LSS in the literature reviewed, which include management support and commitment, organisational culture and change, employee engagement and empowerment, and education and training. However, new CSFs emerged from the practitioner views based on their experience, such as securing buy-in for the OPEX initiative, slowing down the speed of the change process, freeing up capacity for the employee to engage in the OPEX initiative, aligning OPEX strategy and benefits with organisational objectives, clear purpose and benefits, focusing on non-financial benefits, and clear definition of the improvement problem. Research Implications —This study can serve as a resource for researchers and practitioners to understand the importance of CSFs and positioning CSFs for the successful implementation of LSS projects in HEIs and Public Service Organisations. Originality/Value—Limited empirical studies explore the CSFs of LSS methodology implementation in HEIs and Public Service Environments. This study has made a further and new contribution to the existing research in identifying the CSFs of LSS projects in HEIs and public service organisations (PSOs). The TA on the expert interview presents a unique effort to assess OPEX CSFs in HEIs.