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Context: We and others have previously reported associations between a range of social exposures and biological aging. While improvements in socioeconomic status may have health-promoting effects, there may also be health costs resulting from the stress of moving across social categories; results of studies to date have been mixed. Objective: We quantified associations of educational mobility with biological aging and mortality across three generations of the Framingham Heart Study. Sample: The Framingham Health Study is an on-going biennial observational cohort study first initiated in 1948. Since then, two additional cohorts have been recruited, representing the children and grandchildren of the original Framingham cohort and their spouses. We analyzed data from 1,341 participants in the Offspring Cohort and 1,298 participants in the third-generation (Gen3) cohort who had educational attainment data and provided blood samples for genotyping. Exposure: We followed the methods used by Liu and colleagues to link educational records for the Original, Offspring, and Gen3 cohorts, and assigned each participant a cohort-specific z-score for their parents' education and their own education score. We quantified educational mobility using residualized-change and difference scores. The residualized-change approach quantifies mobility as the difference between the participant's own educational attainment and the attainment expected based on their parents' educational attainment. The difference-score approach quantifies mobility as the absolute difference between parental education z-scores and the participant's own education z-score. Outcome: Biological aging is the gradual and progressive decline in system integrity that occurs with advancing chronological age, mediating aging-related disease and disability. We quantified biological aging using six DNA methylation "clocks". These clocks use DNA-methylation marks included on commercial arrays, and which have received substantial attention in the research literature. Analysis: We analyzed patterns of educational mobility and their association with (a) DNA methylation measurements of biological aging; and (b) mortality. We tested how parents' education and an individual's own educational mobility were related to their biological aging and mortality risk. We then conducted mediation analysis to determine if more advanced and faster biological aging mediated associations between life-course education phenotypes and mortality. Results: The mean age of our sample was 66 years (SD=9, 46 of the relationship between educational mobility and mortality was mediated through biological-age advancement. Conclusions and Relevance: Our results are consistent with previous reports that upward educational mobility is associated with less-advanced biological aging and reduced risk of death.