In this longitudinal study, we examined the relations between emotion knowledge in first grade, teacher reports of internalizing and externalizing behaviors from first grade, and children's self-reported internalizing behaviors in fifth grade. At Time 1, we assessed emotion knowledge, expressive vocabulary, caregiver-reported earned income, and teacher-rated internalizing and externalizing behaviors in 7-year-old children from economically disadvantaged families (N = 154). At Time 2, when the children were age 11, we collected children's self-reports of negative emotions, depression, anxiety, and loneliness. First grade teacher-reported externalizing behaviors, but not first grade internalizing behaviors, were positively related to children's self-reports of internalizing behaviors in fifth grade. First grade emotion knowledge accounted for a significant amount of variance in children's self-reports of internalizing symptoms 4 years later, after controlling for per capita earned income, expressive vocabulary, and teacher-reported internalizing and externalizing behaviors in first grade.