Multiphase flow analysis and validation of computational fluid dynamics codes require sophisticated measurement techniques with high spatial and temporal resolution. Imaging techniques are excellent candidates for such as they are able to obtain field quantities. However, for multiphase flows only few modalities are applicable as the frequent change of mechanical, thermodynamic and electrical material properties in multiphase mixtures leads to strongly nonlinear relations in signal propagation. In this chapter we give a basic overview over the physical and technological principles of the most prominent imaging techniques, which are being used for multiphase flow studies today, along with a very general introduction into methods of data processing.