INTRODUCTION: Neighborhood deprivation increases dementia risk, although mechanisms remain unclear. We tested a framework in which modifiable risk factors and cerebral small vessel disease (SVD) mediate the link between neighborhood deprivation and cognition. METHODS: In 585 cognitively healthy midlife adults (ages 40-59), neighborhood deprivation was derived from postcodes, cognition was assessed using the COGNITO, lifestyle risk factors were measured using clinical assessments, and SVD (white matter hyperintensities, lacunes, microbleeds, perivascular spaces) was assessed on 3T magnetic resonance imaging. Multivariate analyses examined association pathways among these variables. RESULTS: Neighborhood deprivation was associated with poorer cognition (r = 0.36, p < 0.001), greater prevalence of modifiable risk factors (r = 0.36, p < 0.001), and greater SVD burden (β = 0.18, p = 0.008). Serial mediation showed that the effects of deprivation on cognition were indirect, possibly operating via lifestyle risk and SVD, explaining 20% of the total effect, whereas SVD alone explained 28%. DISCUSSION: Neighborhood disadvantage relates to poorer cognition, possibly mediated through vascular risk factors and cerebrovascular disease. HIGHLIGHTS: Neighborhood deprivation linked to poorer cognition in healthy midlife adults Deprivation linked to small vessel disease (SVD) and modifiable risk factors (chiefly cardiovascular risk) Association between deprivation and cognition mediated by modifiable risk and SVD Mediation was exclusive to hypertensive SVD, but not cerebral amyloid angiopathy (CAA)-related SVD.