This is a study of the wellbeing of leaders in a New Zealand context. It arose in response to an increasingly complex and turbulent work environment that requires leaders to perform, including investing their full and personal selves into the workplace, above and beyond existing conditions. Clearly, however, being able to function at this level can deplete their inner resources. On the one hand, the performance challenges inherent in the current environment have called for a new approach to leadership called positive leadership. Yet, on the other hand, advances in positive leadership have not adequately addressed the positive antecedents or personal resources required for leaders to survive, let alone thrive, in this environment. In addition, the thesis found that while advances in positive psychology, and to a lesser extent, positive organisational behaviour, focus on wellbeing, they reveal little about the wellbeing of leaders. Therefore, this study makes an original contribution to knowledge by investigating and understanding leaders’ wellbeing. Specifically, the thesis unravels the benefits and complexities of Self Determination Theory (SDT), a eudaimonic theory of wellbeing, and assesses the role of SDT in facilitating additional positive life, mental health and work place outcomes for leaders. This thesis addresses four major research questions: (1) Does SDT aid our understanding of leaders’ wellbeing within the workplace? (2) What role do the various dimensions of SDT play in facilitating leaders’ welfare? (3) While it has been theoretically argued that SDT forms a ‘metamodel’ of wellbeing, can this be empirically supported? (4) Can SDT add to the mounting empirical support for Positive Organisational Behaviour (POB), which focuses on enhancing the positive elements of organisational functioning (Luthans & Avolio, 2009)? The thesis was designed and conducted through four separate studies. These are presented in seven research articles which aim to ascertain the full implications of SDT for leaders. Each is a peer reviewed publication presented as a separate research chapter in the thesis. Accordingly, this thesis is a thesis with publications. Three of the seven research publications have been accepted and are in press in peer reviewed journals; the others have been presented at international peer reviewed conferences and are also under review in various journals as outlined further in chapter two. All studies use a quantitative methodology, although the type of methodology varied across the studies and included structured equation modelling (SEM), moderated regression, mediated regression and multilevel analysis. The seven separate studies are: Study 1 (in chapter three), which investigates the aspirations of leaders’ and their job burnout (n=386, using SEM); Study 2 (in chapter four), which investigates leaders’ motivations, enrichment and job satisfaction (two samples: n=386 and n=205, using SEM); Study 3 (in chapter five), which investigates mindfulness and leaders’ mental health (4 samples: n=202, n=184, n=205, n=107, using mediated regression) as well as the role of psychological capital as a mediator; Study 4 (in chapter six), which investigates perceptions of autonomous support and job outcomes from a team level of analysis (n=457 in 199 teams, using SEM); Study 5 (in chapter seven), which investigates leaders’ three needs for autonomy, competence and relatedness crossing over to employee wellbeing (n=160 leaders, n=368 followers, using multi-level analysis); Study 6 (in chapter eight), which investigates the work-family interface and leaders’ three needs of autonomy, competence and relatedness (n=418, using moderated regression); study 7 (in chapter nine), which represents the entire metamodel of SDT (that is, all of the above dimensions) towards leaders’ organisational citizenship behaviours (n=386, using moderated regression). Each empirical study found conclusive evidence of the beneficial role that SDT provides for leaders in today’s workplaces. Accordingly, the thesis concludes that SDT does provide leaders with an inner resource that they can draw upon to aid their own wellbeing in the current business environment. In addition to providing insight into leaders’ SDT within a New Zealand context, the thesis finds that wellbeing is a pertinent and central issue in leadership research generally. Overall, the seven studies in combination provide a comprehensive model of wellbeing, which provide a resource for POB. Finally the thesis develops and extends previous research on wellbeing for leaders by providing a broader understanding of the benefits of wellbeing. By addressing the theoretical and empirical shortcomings of earlier studies, it also points future researchers to the area of wellbeing studies as central to the enabling of positive leaders and thriving workplaces.