ABSTRACT A significant amount of research has been conducted to understand what makes workplace coaching effective. Several factors, including coach competencies, have been found to contribute to coaching success. Extant literature, however, shows that there is still a knowledge gap in terms of which coach competencies lead to specific coaching outcomes. Some scholars have identified transformative learning (TL) as an outcome of coaching. However, few empirical studies have explored which coach competencies facilitate TL. We adopted a multiple case-study design, with a sample of five coaches and nine senior public-sector executives in South Africa. We conducted a longitudinal study over a period of six months, to observe and assess coach behaviours including how these might lead to TL outcomes. The findings isolate five core coach competencies, their related coach behaviours and the role played by each one in the TL process. These are: creating a safe environment for managing disorienting dilemmas, facilitating self-awareness, motivating and challenging the client, engaging with emotions and holding the client accountable. We propose a framework that can guide practicing coaches who work with leaders and managers, coach trainers and education institutions and HRD practitioners who engage coach services on how to facilitate transformative learning.