<p>While previous research has focused on individual risk factors, few studies have utilized an intersectionality-informed framework to examine how multiple social factors collectively impact depression risk, particularly in the context of childhood adversities. This study investigates the association between adverse childhood experiences (ACEs) and depression while considering the intersecting roles of sex, socioeconomic status (SES), and ethnicity in identifying high-risk population subgroups. Data were drawn from the Canadian Longitudinal Study on Aging (CLSA), a nationally representative prospective cohort comprising over 50,000 adults aged 45 and older. We included 20,559 participants from the Comprehensive cohort who completed both baseline and first follow-up assessments. Depression was measured using a validated scale (CES-D-10). Key variables included ACE exposure, sex, SES, ethnicity, and other sociodemographic covariates. Latent class analysis was conducted to explore latent ACEs groups. Multilevel analysis of individual heterogeneity and discriminatory accuracy (MAIHDA) was employed to investigate whether ACE patterns and intersectional social groups predicted differential risks of depression. Three distinct patterns of ACEs were identified. The high ACE group was associated with an elevated risk of depression, especially among females, individuals with low SES, and non-White groups. This risk was compounded among those with multiple marginalized identities, such as females with low SES and exposure to high ACE, highlighting the cumulative nature of depression vulnerability. In contrast, male sex and high SES were protective, particularly in the absence of ACE exposure. Integrating ACEs with an intersectional framework reveals the complex etiology of depression and underscores the need for targeted, equity-oriented prevention strategies considering cumulative disadvantage.</p>