Background: The study aims were to: 1) examine associations between deprivation at age 7 and health outcomes at age 7 and 14, (2) determine whether a deprivation gradient to health outcomes exists at age 7 and 14, and (3) assess the extent to which health outcomes at age 7 are associated with health outcomes at age 14. Methods: Data were from wave four and six of the Millennium Cohort Study. Health outcome measures were weight status, and Strengths and Difficulties Questionnaire measured mental health problems. Deprivation was determined using the 2004 English Indices of Multiple Deprivation. Adjusted logistic and multinomial logistic regressions were conducted. Results: 6109 children (1890 girls) had complete data. Overweight, obesity, and mental health problems were greatest among children in the highest deprivation decile at age 7 and 14 (p < 0.001). Health outcomes at age 7 were significantly associated with health outcomes at age 14 (p < 0.001). Conclusions: A marked social gradient to weight status and mental health was evident at age 7 and 14, and no evidence of equalisation was found. Weight status and mental health in childhood is strongly associated with weight status and mental health in adolescence.