A synthesis of the geology of the Belgian continental shelf is here presented. The main part of this document is dedicated to the review of the lithostratigraphy, geotechnical properties, geometry and distribution of the Tertiary and Quaternary deposits. The data compilation, review and assessment have been conducted from the numerous existing studies and large data sets, available offshore, but also onland when offshore data were scarce or lacking. Three main projects have enabled to collect the offshore data: (1) the project âSeismic stratigraphy, Southern Bight, North Seaâ (RCMG, City of London Polytechnic/NERC, University of Caen/CNRS); (2) the project âSeismisch onderzoek op het Belgisch Continentaal Plat. Eerste faze. Ontginningszone 2â (MEZ/Administratie van het Mijnwezen, RCMG); (3) the project âStudie oppervlaktelaag van het Belgisch Continentaal Plat. Seismisch prospectie sector Bâ MEZ/Belgian Geological Survey-BGD, RCMG). Data consist mainly of seismic profiles (16,000 km), cores (79) and cone penetration tests (CPTs, 177). All the data have been digitised and integrated in appropriate georeferenced softwares. Synthetic integrated maps and tables have been produced, aimed to provide the end-users with clear and directly usable information. This synthesis has been conducted in the framework of the project âOptimal Offshore Wind Energy Developments in Belgiumâ, financed by the Belgian federal government (Federal Office for Scientific, Technical and Cultural Affairs). This project is in keeping with the part I project network âProduction patterns and sustainable consumptionâ of the PADD II program. Objectives of this project consisted in providing recommendations for the selection of sites that are convenient with respect to the stability of offshore wind structures and the minimisation of geo-environmental impacts.