Abstract: Social determinants of health (SDOH) have an enormous impact on human health and behavior, although their possible effects on canine behavior have received limited scientific attention. The goals of this observational cohort study were to identify associations between canine behavior, household environments, and zip code-level proxies for human SDOH, and to explore longitudinal impacts on behavior. We used an existing dataset of C-BARQ behavioral assessments from 3044 golden retrievers in the United States, including up to eight years of data per dog collected between 2012 and 2023. The data were analyzed using linear mixed effect models and generalized estimating equations. We found dogs from single-dog homes had increased odds of dog-directed fear (OR 1.44, 95 % CI 1.30–1.61) and poorer trainability, particularly during early adulthood (F=14.32, p < 0.001). Sleeping in the owners’ bed was associated with increased aggression towards strangers, and a greater reduction in trainability (F=20.71, p < 0.001) and energy with age (F=8.20, p = 0.004). Dogs in the most densely populated neighborhoods had greater odds of showing aggression to strangers compared with dogs in sparsely (OR 0.78, 95 % CI 0.63–0.95) or moderately populated neighborhoods (OR 0.73, 95 % CI 0.60–0.90). Together, our findings illustrate how conspecific relationships, human interactions, home and neighborhood environments affect dog behavior, and show, for the first time, that household characteristics and ownership behaviors have differential impacts on behavior across the lifespan. Future studies including more diverse human and canine populations are needed to provide further insights about the impacts of SDOH on dog health and welfare.