OBJECTIVE: We assessed trends in educational inequalities in obesity-attributable mortality (OAM) and their contribution to educational inequalities in all-cause mortality for people aged 30 years and older, in England and Wales (1991-2017), Finland (1978-2017), and Italy (1990-2018). METHODS: In our population-level study, we estimated the shares of all-cause mortality due to OAM by educational level (i.e., low, middle, and high) by applying the population-attributable fraction formula to harmonized obesity prevalence data by educational level, along with sex- and age-specific relative risks of dying from obesity. We obtained OAM rates by multiplying the shares with individually linked all-cause mortality data by educational level. We measured absolute inequalities in OAM and all-cause mortality by the slope index of inequality. RESULTS: OAM largely increased for the different sex- and education-specific populations and increased most strongly for those with low educational level up to 2010 to 2015. Educational inequalities in OAM initially increased but stabilized or declined from at least 2008 onward. Obesity contributed, on average, 15% to absolute educational inequalities in all-cause mortality in 1991 through 2017. CONCLUSIONS: The mortality impact of the obesity epidemic by educational level changed over time. Although the observed change from increasing to declining or stable educational inequalities is encouraging, reducing OAM in all socioeconomic groups remains a challenge.