According to several theories, people differ in their sensitivity to environmental influences with some more susceptible than others to both supportiveandadverse contextual conditions. Such differences inenvironmental sensitivityhave a genetic basis but are also shaped by environmental factors. Herein we narratively build on our previous work proposing that prenatal experiences contribute to the development of environmental sensitivity. This hypothesis ofprenatal programming of postnatal plasticityhas considerable empirical support. After presenting illustrative animal and human evidence consistent with this claim, we discuss a range of biological mechanisms likely involved in the pathway from prenatal stress exposure to postnatal environmental sensitivity. We also consider work suggesting that genetic differences, gender, as well as the timing, duration and intensity of prenatal exposures may moderate the effects of prenatal programming on postnatal environmental susceptibility or sensitivity. Before concluding, we highlight “unknowns in the prenatal programming of environmental sensitivity” and their practical implications. Ultimately, we conclude that prenatal stress does not necessarily predispose individuals to problematical development, but rather increases sensitivity to both adverse and supportive postnatal contexts. Thus, prenatal stress may actually foster positive development if paired with supportive and caring postnatal environments.