Wind energy deployment varies widely across regions and this variation cannot be explained by differences in natural wind resources alone. Evidence suggests that institutional factors beyond physical wind resources can influence the deployment of wind energy systems. Building on the work of Toke et al. (2008), this study takes a historical institutionalist approach to examine the main factors influencing wind energy deployment across four Canadian provinces Canada: Alberta, Manitoba, Ontario and Nova Scotia. Our case studies suggest that wind energy deployment depends upon a combination of indirect causal factors landscape values, political and social movements, government electricity policy, provincial electricity market structure and incumbent generation technologies and direct causal factors grid architecture, ownership patterns, renewable incentive programs, planning and approvals processes and stakeholder support and opposition. (C) 2010 Elsevier Ltd. All rights reserved.