Socioeconomic disadvantage is associated with higher obesity risk in older adults, but whether walkable neighborhoods modify these inequalities remains unclear. We examined whether neighborhood walkability moderates the association between area-level socioeconomic status (SES) and adiposity among older adults with overweight or obesity living in Mediterranean cities. This cross-sectional study analyzed baseline data from 1286 urban-dwelling adults aged 55 to 75 years with overweight or obesity and metabolic syndrome residing in six Andalusian cities. Area-level SES was assessed using the 2011 Spanish Deprivation Index, and neighborhood walkability was derived from an open-source index incorporating population density, street intersection density, and access to daily amenities. Adiposity outcomes included waist circumference, waist-to-hip ratio, and a body shape index, all objectively measured. Two-level linear regression models, with individuals nested within census tracts, evaluated SES-walkability interactions while adjusting for demographic and lifestyle factors. No overall differences in adiposity were observed between higher- and lower-SES neighborhoods. However, walkability significantly modified the SES-adiposity association. In highly walkable and dense neighborhoods, participants living in more deprived areas had larger waist circumference and higher body shape index compared with those in less deprived areas, indicating a steeper SES gradient in central adiposity. In low-walkability neighborhoods, SES differences in central adiposity were minimal. No interaction was observed for body mass index. Highly walkable urban environments may therefore amplify socioeconomic inequalities in abdominal obesity among older Mediterranean adults with overweight or obesity. Urban planning strategies promoting walkability should incorporate equity-focused, age-friendly approaches to ensure benefits reach socioeconomically disadvantaged populations.