© 2017 Elsevier Ltd Cities around the world have launched greening initiatives to reduce their carbon footprint and to become more sustainable. At the same time, they have also sought to use these initiatives to position themselves as climate change leaders and green champions. This paper focuses on the City of Vancouver's Greenest City 2020 Action Plan as urban policy strategy to reduce carbon emissions. Based on interviews with actors and experts involved in the development and implementation of the plan, the paper evaluates the role green leadership aspirations play in shaping urban climate change policy and how policy makers and stakeholders use policy to position the city and its greening initiatives locally and globally. In particular, it analyzes the role of competitive positioning and green leadership in sustainability initiatives and change within and beyond urban boundaries. While leadership suggests increased buy-in of residents and those involved in the implementation of the strategy and multiplication effects through learning within the region and between (peer) cities, it can also pose challenges as the interest in meeting leadership claims can impede more radical change through specific targets and implementation strategies and challenge other sustainability objectives.