Using a longitudinal design (Wave 1 n = 164, Mage = 3.57 years, 54% female, predominantly White and French-speaking), the current study sought to answer two questions: 1) does poverty influence children’s negative emotionality through heightened family-level, poverty-related stress? and 2) is negative emotionality, in turn, predictive of adolescent internalizing symptoms, externalizing behaviors, cognitive abilities, and physical health? Results confirmed an indirect pathway from family poverty to child emotionality through poverty-related stress. In addition, negative emotionality was associated with adolescent internalizing symptoms, attention difficulties, and physical health, but not externalizing symptoms, even when controlling for early poverty exposure.