The functional properties of multiphase systems depend not only on the properties of the constituents, but also on the microstructure. This microstructure, which develops during processing, can be tailored by steering flow conditions and altering component characteristics. Hence, knowledge of the relations between flow and microstructure is essential to tailor product properties. In this research, flow-induced microstructure is studied for a wide range of multiphase materials including polymer blends, polymer nanocomposites, suspensions, emulsions and food products. The focus is on experimental studies, which are used as a basis to develop scaling relations and models. By using in-situ and time-resolved structure characterization techniques in combination with diagnostic flow types, it is attempted to develop a fundamental understanding of flow-induced morphology development. Thereto, on the one hand, direct visualization via rheo-optical techniques combining for example microscopy or light scattering with flow cells is used. On the other hand, by developing relations between rheology and microstructure for different material classes, the potential of rheology as an indirect structure probing technique is exploited and extended. Efforts are also directed towards improvement and development of experimental setups and protocols.