Purpose: There is a growing interest in showcasing what building school capacity looks like empirically. Although there has been considerable focus on school reforms globally, the actual impact of such attempts on building school capacity, particularly in a non-Western context, remains less explored. This paper aims to illustrate the process of building school capacity in a Lebanese private school following its participation in a school-based improvement project. Design/methodology/approach: Data were gathered using focus groups and individual interviews, document analysis and participant observation by the researcher. Thematic analysis and emergent coding techniques were conducted, and the findings were compared to existing literature on school capacity building. Findings: Findings of this study explore various facets of school capacity for leading school-based improvement. They show building of personal, interpersonal and organizational capacities of the case school as termed by Mitchell and Sackney's (2011) theoretical framework. Originality/value: The paper demonstrates the process of building school capacity in a non-Western school context where participating in a school-university partnership is unusual. Being a case study, it explores the complex process of building school capacity in a given context, offering an in-depth and more nuanced understanding of this topic and illuminating its actionable and transformative effects for sustainable school improvement. It enriches the field of building school capacity by expanding to underexamined societies, especially in the Arab region, setting a foundation for future comparative research about this topic in diverse educational settings.