Microstresses and dislocation distributions have important effects on the properties of many materials including dual phase (DP) steels and HSLA steels investigated in this thesis. Two complementary experimental techniques were used for the measurements: (i) electron backscatter diffraction (EBSD) and (ii) X-ray diffraction (XRD) line profile analysis (LPA). Nanoindentation was also used to investigate the variation in hardness within DP steels.