This research explores the leadership knowing-doing gap, a challenge that is compelling in practice yet novel in leadership theory and research. The main purpose of this research is to understand the leadership knowing-doing gap experience from the perspective of leaders, focusing on the role of leader fear and the leadership context. The research explores how leaders may translate, to varying degrees in different contexts, their leadership knowledge into leadership action. It looks at the emotion of fear in leaders, and how its potential behavioural responses may constrain the transfer of leadership knowledge into leadership action. It also looks at how the leadership context may influence the leadership knowing-doing gap. The study uses a qualitative research design relying on a phenomenological approach for data collection and analysis. It pursued in-depth interviews with 22 leaders in the United Kingdom, across various industries and organisational levels. Interviews were semi-structured and utilised critical incident technique to delve into situations in which the leadership knowing-doing gap and fear manifested in the experiences of participants within their contexts of leadership. Findings provide insights into the experience of the leadership knowing-doing gap, pointing to cognitive, affective and behavioural aspects of the experience. Furthermore, findings shed light on the different forms of fear that leaders may experience in the workplace, and how these may influence the dynamics of the leadership knowing-doing gap. Leaders may respond to fear by avoiding behaviour, thus creating or widening the gap on the one hand, or by approaching behaviour, therefore preventing or closing the gap on the other hand. Moreover, findings indicate that the leadership knowing-doing gap may be directly or indirectly shaped by the leadership context, and that fear and the leadership knowing-doing gap may be influenced by, and potentially impact on, leaders and their leadership contexts. This research contributes towards existing approaches to leadership and workplace emotions, with the hope of spurring interest in future research on the topic.