It is widely recognised that interaction and collaboration between staff in higher education institutions (HEIs) is less than optimal, and this is exacerbated by siloisation and a divide between faculty and other staff. The consequent lack of staff knowledge sharing has a significant negative impact on the overall performance of these organisations. This study examines how enterprise social networks (ESN) can enable staff knowledge sharing in virtual communities of practice (vCoP) in HEIs. The research is framed as an Action Research project and addresses a number of research questions focussed on the antecedents for staff knowledge sharing; the dominant problems associated with ESN implementation and vCoP participation; the key motivators for staff to adopt the use of ESN and participate in vCoP; and the perceived benefits of knowledge sharing for both the organisation and for staff members. The research design developed a conceptual model for empirical testing and the study findings support the model as well as yielding additional inputs and further insight. The key findings indicate that organisational culture and structure are major barriers to staff knowledge sharing and this is exacerbated by the divide between faculty and other staff. Management have the most important role to play in shaping a knowledge sharing environment, and this involves facilitating the promotion and creation of vCoP. Community leaders and champions are pivotal to the success of vCoP and the development of the ESN. Staff must also be suitably motivated to participate in the knowledge sharing environment if a critical mass of users is to be reached to ensure sustainability of the ESN. Changing the prevalent transactional culture in HEIs to stimulate knowledge sharing requires transformational leaders who recognize the opportunities and benefits that enhanced interaction and collaboration will bring. The study findings provide an opportunity for educationalists to better understand the scope and the impact of employing ESN platforms for knowledge sharing. In seeking to determine the drivers and barriers to sustainable use, this research should also be of interest to practitioners and researchers undertaking similar projects.