Purpose – While it is well known that leadership can play an important role in engendering effective knowledge management activity, relatively little is known about which styles of leadership are most appropriate for this task. The purpose of this paper is to contribute to theory by exploring dimensions of leadership as presented by Avolio and Bass (Transformational, Transactional and Passive-Avoidance Leadership) and the dimensions of organisational knowledge management activity as presented by Maier and Mosley through a survey of primary knowledge managers from information and communications technology (ICT) organisations in the UK. Design/methodology/approach – The paper presents the results of a quantitative survey of 111 primary knowledge managers from ICT organisations in the UK. Findings – The key finding is that when primary knowledge managers within organisations adopt the Transformational and Transactional leadership styles, there is a notable increase in knowledge management activity. Given the results, the authors argue that organisations must be cognisant of the leadership style adopted by their knowledge managers and that it is important that both the Transformational and Transactional leadership styles are mastered and can be employed by knowledge managers within organisations. Originality/value – The paper provides analysis of two well-known leadership styles and a full range of knowledge management activity, providing insights for practitioners and theorists alike.