Not all children exposed to adverse environments develop mental health problems. Many children exhibit enormous resilience in the face of exposure to serious forms of adversity. What makes children more or less vulnerable to the mental health consequences of adversity? Identifying factors that magnify or buffer children from these effects can inform intervention strategies that prevent the onset of psychopathology among children who are most vulnerable. Our work has identified a variety of protective factors that could represent potential targets for intervention. For example, we have found in multiple studies that children who are sensitive to positive and rewarding cues are less likely to develop depression after exposure to abuse and other forms of adversity. We have also contributed to the search for sensitive periods when certain types of inputs from the environment are particularly influential in shaping developmental processes. We have identified sensitive periods in emotional and neurobiological development, when developing systems are most strongly impacted by environmental experience. This work can help to better target interventions for children to capitalize on periods of heightened plasticity when interventions are likely to be maximally efficacious.