Longitudinal links between childhood family income and adult outcomes are well documented. However, research on childhood income volatility and young adult outcomes is limited. This study utilizes data from the NLSY (N = 6,410) to examine how childhood family income and income volatility relate to socioeconomic outcomes and mental/behavioral health in emerging adulthood. Results show that lower childhood income was associated with young adult socioeconomic and behavioral health outcomes. Higher income volatility was associated with increased depression and teen parenthood during young adulthood. Additional analyses examining trajectories of income volatility illustrated that children in families with unstable income trajectories (i.e., frequent income losses and gains) showed higher depression scores than those with stable trajectories. These findings suggest that income volatility, not just income level or income loss, is important to consider when studying economic disparities in young adult outcomes. Implications for policies and programs for low-income, high-volatility households are discussed.