The present study examines socio-emotional learning (SEL) across the prekindergarten year in a low income, racially and ethnically diverse sample of Chicago Public School students (N = 2,630). The sample included participants of the Child-Parent Center early educational intervention program (N = 1,724) and a propensity-score matched comparison group (N = 906). At the beginning of the prekindergarten year, teachers rated boys and lower income participants as having relatively lower SEL skills, and CPC participants and older children as having slightly higher SEL skills. Over time, CPC participants exhibited significantly greater rates of SEL growth, ending the prekindergarten year with teacher-rated SEL scores that were an average 10.30% higher than control participants. There were no significant differences in SEL growth over time by sex or family income. (author abstract)