The purpose of this report is to assess whether investment in Green Infrastructure increases economic growth, based on the available evidence. We take Green Infrastructure (GI) to mean a planned approach to the delivery of nature in the city in order to provide benefits to residents. This includes features such as street trees, gardens, green roofs, community forests, parks, rivers, canals and wetlands. Economic growth is defined as an increase in economic activity as measured by Gross Domestic Product (GDP). Specifically we are interested in whether investment in GI increases GDP compared to what would have happened without the investment. We approached the question in two ways, firstly considering the weight of evidence supporting relevant logic chains and secondly reviewing case studies.