This study exploits variations in the timing of welfare reform implementation in the U.S. in the 1990s to identify plausibly causal effects of welfare reform on a range of social behaviors of the next generation as they transition to adulthood. We focus on behaviors that are important for socioeconomic and health trajectories, estimate effects by gender, and explore potentially mediating factors. Welfare reform had no favorable effects on any of the youth behaviors examined and led to decreased volunteering among girls, increases in skipping school, damaging property, and fighting among boys, and increases in smoking and drug use among both boys and girls, with larger effects for boys (e.g., ~6% for boys compared to 4% for girls for any substance use). Maternal employment, supervision, and child’s employment explain little of the effects. Overall, the intergenerational effects of welfare reform on adolescent behaviors were unfavorable, particularly for boys, and do not support longstanding arguments that limiting cash assistance leads to responsible behavior in the next generation. As such, the favorable effects of welfare reform for women may have come at a cost to the next generation, particularly to boys who have been falling behind girls in high school completion for decades.