In modeling sheet metal forming and springback, the inputs for calibration, such as stress-strain curves and Young’s/unloading modulus, are typically based on the uniaxial tension case; in other words, material behavior is assumed to be “symmetric” under both tension and compression loading conditions. In this work, we shed some light on this assumption via a comprehensive experimental investigation on the tension–compression asymmetry in several grades of dual phase steels, including DP590, DP780, DP980, and DP1180. The differences in the macro behavior of these grades are correlated to the different ferrite-to-Martensite phase fractions. A ferritic mild steel and a martensitic steel were also considered as references for the comparison. The microstructures of the target steel grades were examined and compared with each other to demonstrate that the tension–compression asymmetry arise not only from crystallographic texture but also from the directional substructure induced by the severe pre-straining.