OBJECTIVE: Research conducted on school-based interventions suggests that school connectedness protects against a variety of risk behaviors, including substance abuse, delinquency and sedentary behavior. The line of research is extended by examining the link between college expectations and early adult weight gain using nationally representative panel data from thirty cohorts of American high school seniors followed prospectively to age 30 in the Monitoring the Future Study (1986-2009). DESIGN AND METHODS: Growth mixture models identified two latent classes of trajectories of body mass index (BMI) from age 19 to 30: a persistently overweight class (BMI >/= 25) and a second class exhibiting more moderate growth in BMI to age 30. RESULTS: Compared to those who did not expect to graduate from college, students fully expecting to graduate from college had 34% lower odds of being in the persistently overweight class (adjusted odds ratio = 0.66, 95% confidence interval = 0.54, 0.81), controlling for academic performance and socioeconomic status. CONCLUSIONS: Successful prevention of obesity early in the life course is based on a multifactorial approach incorporating strategies that address the contexts in which adolescents are embedded. The school setting may be one avenue where successful educational attachment could have positive consequences for subsequent weight gain in early adulthood.