This presentation shows the approach of making use of Knowledge Graphs in Data Spaces and Data Markets to foster data- and semantic interoperability. Interoperability is the enabler of efficient and sustainable data sharing between organisations, either in a certain industry or across industries, either in the form of data trading or as data collaborations. This talk will explain the basic principles of Data Spaces, draw the problem statement of interoperability for value-added data sharing, and present the solution approach – including real world examples – of using Knowledge Graphs to foster Interoperability in Data Spaces