AbstractThe Southern European Atlantic diet (SEAD) is the traditional dietary pattern of north-western Spain and northern Portugal, but it may resemble that of other European countries. The SEAD has been found associated with lower risk for myocardial infarction and mortality. Since dietary patterns may also influence mental health, we examined the association between the SEAD and depression risk in southern, central, eastern, and western European populations. We conducted a prospective analysis of five cohorts (13,297 participants aged 45–92 years, free of depression at baseline): Seniors-ENRICA-1 and Seniors-ENRICA-2 (Spain), HAPIEE (Czechia and Poland), and Whitehall-II (United Kingdom). The SEAD comprised cod, other fresh fish, red meat and pork products, dairy, legumes and vegetables, vegetable soup, potatoes, whole-grain bread, and moderate wine consumption. Depression at follow-up was defined according to presence of depressive symptoms (based on available scales), use of prescribed antidepressants, inpatient admissions, or self-reported diagnosis. Associations were adjusted for sociodemographic, lifestyle, and dietary variables. During a median follow-up of 3.9 years (interquartile range 3.4–4.9), there were 1437 new depression cases. Higher adherence to the SEAD was associated with lower depression risk in the pooled sample. Individual food groups showed a similar tendency, albeit non-significant. The fully adjusted odds ratio (95% confidence interval) per 1-standard deviation increment in the SEAD was 0.91 (0.86, 0.96). This association was rather consistent across countries [Spain = 0.86 (0.75, 0.99), Czechia = 0.86 (0.75, 0.99), Poland = 0.97 (0.89, 1.06), United Kingdom = 0.85 (0.75, 0.97); p for interaction = 0.24], and was of similar magnitude as that found for existing healthy dietary patterns. In conclusion, the SEAD was associated with lower depression risk across European populations. This may support the development of mood disorder guidelines for Southern European Atlantic regions based on their traditional diet, and for central, eastern, and western European populations based on the SEAD food groups that are culturally rooted in these places.