Wild Streets is a free mobile app that empowers citizens to ‘green’ their cityscape using augmented reality and scientific data for tree-selection. The transformation towards sustainable and smart cities with minimum carbon footprints is, without a doubt, one of the greatest challenges of our time. There is an urgent need for more tech-based solutions to include and engage civil society in this process. The idea of city dwellers co-creating their cities together with the private and public sector is on the rise with more and more cities across the world successfully involving people in planning decisions. Enhancement of nature in the urban image is often picked as a top priority. Wild Streets sets out to make the task of designing our cities’ green urban infrastructure a participatory project. The project comes at a time when political and public support for greening initiatives at all scales is increasing. Wild Streets aims to serve as a transformative facilitating tool for these projects and for the rapid transition towards a greener urban future. Wild Streets pushes the notion of what is possible in the world of city planning and citizens involvement in shaping the green cities of tomorrow—it offers an inclusive, fun, and innovative approach to trigger a green makeover of the cityscape by infusing the public with a new sense of ownership of their city, whilst making it more sustainable and liveable.