ObjectiveThis study assessed levels of child-reported parent and family social support associated with physical activity (PA) and fruit and vegetable consumption (FVC) by ethnicity among a lower-income sample of US elementary school students. DesignAnalysis of cross-sectional baseline data of an elementary school–based study from fall, 2010. SettingNineteen schools in a large urban school district in central Texas. ParticipantsFourth- and fifth-grade children (n = 581) and their parents. Main Outcome MeasuresChild-reported parental and family social support, 7-day PA, previous day FVC, and weight status. AnalysisChild-reported social support, PA, and FVC using descriptive statistics, ANOVA, chi-square tests, and multiple linear regressions were examined. ResultsChild-reported parent and family social support varied by ethnicity (P < .01), with Hispanic children consistently reporting the lowest support. Child-reported social support had a positive association across the 3 energy-balance related behaviors examined (P < .001). Conclusions and ImplicationsWhereas child-reported social support was associated with energy balance–related behaviors across ethnic groups, lower perceived parental and family social support for Hispanic children may represent an important opportunity for intervention.