Socio-economic variations in health exist for a wide range of health outcomes, including oral health and oral-health-related quality of life (OHRQoL). Less is known regarding how socio-economic trajectories may influence oral health and OHRQoL. This study examined whether social mobility is related to the number of teeth retained by age 50 years and OHRQoL measured at the same time, using data from the Newcastle Thousand Families Study, a birth cohort established in 1947. Women remaining in the non-manual class had the greatest tooth retention. While promotion of a healthier lifestyle and continued improvements in oral hygiene throughout life appear to be the public health interventions most likely to improve oral health into middle age, there may be sub-groups of the population on which different approaches in terms of public health interventions need to be focused.