Recent work indicates that a general factor, often referred to as the p-factor, underlies nearly all forms of psychopathology. Although the criterion validity and utility of this general factor have been well supported, questions remain about the substantive meaning of the p-factor. The purpose of the present longitudinal study was to empirically test the hypothesis that the p-factor reflects dysregulation arising from a combination of high dispositional negative emotionality and low executive control. The current study examined preschool executive control, measured using a battery of 9 developmentally appropriate executive control tasks, as a moderator of the association between preschool negative emotionality and both concurrent and subsequent levels of general psychopathology in preschool and elementary school using a community sample (N = 497). Latent moderated structural equation models demonstrated that preschool executive control significantly moderated the associations between preschool negative emotionality and general psychopathology both in preschool and approximately 5 years later in elementary school. These results suggest that the general factor of psychopathology may reflect dysregulation arising from a tendency to experience high negative affect, without sufficient executive control to effectively down-regulate that affect. This work has important implications for identifying transdiagnostic targets for prevention and intervention efforts, as well as furthering understanding of the substantive meaning and construct validity of the general factor of psychopathology. (PsycInfo Database Record (c) 2022 APA, all rights reserved).