Childhood obesity not only has serious long-term health implications, but also the potential to affect an individual’s economic prosperity throughout adulthood. Using British cohort data, we investigate the impact of childhood and adolescent obesity on an individual’s future household income when they are in their 30’s, 40’s and 50’s. We adjust for a rich set of childhood demographic characteristics and social circumstances, including the parent’s education, social class, income and marital status to isolate the effect of youth obesity on adult economic prosperity. We find that obesity at age 16 is associated with significantly lower levels of household income throughout adulthood (by approximately 14%, p<0.05) for females, but not males. The household income penalty is greater for females who are also obese in adulthood. Additional estimations on the impact of adolescent obesity on employment, wages, marriage and spousal income suggest that the household income penalty for females is driven by a lower likelihood of marriage and lower spousal incomes rather than through wage penalties in the labour market. Lower spousal incomes are associated with adolescent obesity irrespective of whether the young female remains obese in adulthood. Our findings suggest that even after adjusting for early family social circumstances and child characteristics, obesity in adolescence can has significant negative implications for an individual’s social and economic success several decades later.