The 20th annual Social Simulation Conference (SSC 2025) will take place from 25th to 29th August 2025 at Delft University of Technology, the Netherlands. The conference is one of the key activities of the European Social Simulation Association (ESSA), aimed at promoting social simulation in Europe and elsewhere. This year’s special theme is “Social simulation in a socio-technical context: embracing societies’ complexities.” A theme fitting to an engineering university that, through the faculty Technology, Policy and Management, bridges engineering to the many disciplines that are present in the ESSA community. Being open minded to other perspectives is in our DNA. In other words: we welcome you wholeheartedly to Delft!