Project-based organisational forms are becoming more and more prevalent in many industries, and leadership influences projects' success ultimately impacting the organisational performance. Two types of leadership styles have been explored: vertical and horizontal. This study aims to identify the nature and balance of vertical and horizontal leadership in projects to allow project managers to consciously poly these approaches in different situations. A case study-based approach is adopted wherein, two case studies from India and three case studies from Australia are included . A comparative study of leadership styles is performed to find the best contextual fit for leadership styles. The findings reveal that that national cultural is not a major factor in influencing project leadership. Rather, organisational culture and a shared understanding on leadership practices is what influences whether vertical or horizontal leadership will be more prevalent. Senior leaders' initiatives to create and support a culture of sharing ideasand decisions, backed by project manager's approach enable effective balance between horizontal and vertical leadership. Horizontal leadership is further by regular meetings and social interactions. Prevalence of horizontal leaderships is demonstrated in technical decisions, as team members have the best expertise to address technical issues. In contrast, strategic decisions are normally discussed with the project manager and often escalated to senior leaders for decisions