With an ever-ageing population in developed countries, healthy ageing is an emerging public health priority for securing citizens’ quality of life and minimizing healthcare associated costs. While adherence to the Mediterranean diet is associated with numerous health benefits and deterrence of age-related disorders, a comprehensive review of the current evidence to guide further public health interventions is lacking. This study systematically assessed, according to PRISMA guidelines, current evidence arising from observational studies regarding the potential impact of adherence to the Mediterranean diet on healthy ageing among elder adults. Of 509 initially retrieved unique items, 9 studies (including 2 cross-sectional and 7 prospective cohort studies) were reviewed. The reviewed evidence support that adherence to the Mediterranean diet during midlife was associated with 36%–46% greater likelihood of healthy ageing. Among the elderly, adherence to the Mediterranean diet was significantly associated with healthy ageing, while diets similar to that of the Mediterranean diet were associated with 269% greater likelihood of successful ageing and 33% reduction in mortality risk. Therefore, public health interventions aimed at promoting adherence to the Mediterranean diet, particularly among the elderly, may propagate healthy ageing and diminish the healthcare associated costs associated with age-related morbidity and mortality.