Abstract: The vegetation in semi-natural habitats supports ecosystem services (ES) essential for the development of sustainable farming systems. QuESSA aims to quantify some of the key ES (e.g. pollination and biocontrol) derived from semi-natural habitats (SNH) for the main European cropping and farming systems. This will be achieved by identifying key SNH according to their potential to support selected ES based upon vegetation traits. The ES delivery will then be verified through field studies in 16 case studies covering the predominant European cropping systems. A case study is defined by a unique combination of region, crop species, and service. Data will parameterise spatially explicit models to determine how vegetation composition, management, shape, area, and placement of SNH in agricultural landscapes affect the distribution of ES from farm to landscape levels. To investigate synergies and trade-offs in ES, multi-criteria analysis will be developed to combine a suite of modules in an integrative modelling framework. The project will produce guidelines, make recommendations to local, national and EU stakeholders and provide a web-based tool for farmers to enhance exploitation of semi-natural habitats for ES provision.