BackgroundDisasters are increasing in frequency and intensity due to climate change. Youth are the largest and most vulnerable group exposed to disasters. More evidence is needed regarding how youth mental health and health behaviors vary based on disaster exposure, how mental health influences health behaviors, and how diverse groups of youth may be differentially affected. MethodsUsing data from the Youth Risk Behavior Survey and Federal Emergency Management Agency, we examined the impact of Hurricane Sandy (2012) on mental health (sadness, suicidality) and health behaviors (substance use, physical activity, screen time, sexual behaviors) of 240,365 youth. Difference-in-differences regression analyses evaluated pre-disaster (2005–2011) and post-disaster (2013–2019) changes. ResultsThere were 83,442 (34.7 %) adolescents (51.2 % female, 18.1 % non-Hispanic White) located in 6 districts exposed to Hurricane Sandy and 156,923 (65.3 %) adolescents located in 13 non-exposed districts. Exposure was associated with differences in substance use, physical (in)activity, and risky sexual behaviors, but not mental health outcomes. Mental health did not moderate the association between disaster exposure and health behaviors. Hispanic adolescents and those identifying as Other races/ethnicities were most vulnerable to post-disaster negative health outcomes. LimitationsStudy limitations include questionnaire design, cross-sectional data, sampling, and possible response biases. ConclusionsFindings provide critical information about youth mental health and health behaviors following disasters, as well as how youth may differ in their responses. Findings provide guidance for early identification and resource allocation for youth at higher risk for post-disaster health issues.