In modem technical applications components manufactured from composite materials play an increasingly important role. However, internal interfaces between composites' constituents are often characterized by the existence of significant residual stresses formed in the process of manufacturing of the composite material. Reliable estimates of these stresses by non-destructive testing techniques have become an essential requirement for the efficient design of composite materials and structures. In this paper residual stress measurements based on neutron diffraction in various types of multiphase materials are presented. Measurements were performed at the HB4 and HB5 powder and stress diffractometers at the High Flux Reactor (HFR), Petten. Two thermal barrier coatings (TBC) deposited by plasma spraying were tested to evaluate the stress distribution close to the metal/ceramic interface. Both test results consistently show significant residual stress levels near the material interface with compression in the substrate. Finally, state-of-the-art continuous fibre reinforced ceramic matrix composite (CFCC) specimens have been tested in order to characterize their microstructure, including measurement of residual stresses. Significant residual stress relaxation is found in fatigued CFCCs.