This article examines associations between the Great Recession and 4 aspects of 9-year olds' behavior--aggression (externalizing), anxiety/depression (internalizing), alcohol and drug use, and vandalism-using the Fragile Families and Child Wellbeing Study, a longitudinal birth cohort drawn from 20 U.S. cities (21% White, 50% Black, 26% Hispanic, and 3% other race/ethnicity). The study was in the field for the 9-year follow-up right before and during the Great Recession (2007-2010; N = 3,311). Interview dates (month) were linked to the national Consumer Sentiment Index (CSI), calculated from a national probability sample drawn monthly to assess consumer confidence and uncertainty about the economy, as well as to data on local unemployment rates. Controlling for city-fixed effects and extensive controls (including prior child behavior at age 5), we find that greater uncertainty as measured by the CSI was associated with higher rates of all 4 behavior problems for boys (in both maternal and child reports). Such associations were not found for girls (all gender differences were significant). Links between the CSI and boys' behavior problems were concentrated in single-parent families and were partially explained by parenting behaviors. Local unemployment rates, in contrast, had fewer associations with children's behavior, suggesting that in the Great Recession, what was most meaningful for child behavior problems was the uncertainty about the national economy, rather than local labor markets.