Early life environmental toxicant exposure is associated with adverse physical and mental health, yet individual susceptibility varies. Psychosocial exposures, like socioeconomic disadvantage and stress, frequently co-occur with toxicant exposure and also influence health outcomes, but are often studied in isolation. This scoping review maps existing literature examining joint environmental toxicant and psychosocial exposures and health outcomes across the life course. Following PRISMA-ScR guidelines, we searched PubMed, PsycINFO, Web of Science, and Embase in July 2025 using terms related to toxicants and psychosocial exposures. Two reviewers independently screened titles/abstracts and full texts. Inclusion/exclusion criteria were defined a priori using a Population, Concept, and Context (PCC) framework. We included original human studies examining joint toxicant and psychosocial exposures in relation to physical or mental health outcomes. We excluded air pollution, animal models, interventions, and neurocognitive and genetic outcome studies. Findings were synthesized narratively. Fifteen studies met inclusion criteria. Metals and phthalates were most commonly assessed. Psychosocial exposures were typically operationalized as socioeconomic disadvantage, perceived stress, or discrimination. Evidence was concentrated in prenatal exposures and pregnancy or birth, with few studies evaluating childhood, adolescent, or adult health. Most studies used interaction or stratified regression approaches and few employed mixture or cumulative risk methods. This review highlights important methodological opportunities for future research, including integrating environmental toxicant and psychosocial exposures and applying analytical methods that better capture real-world co-exposures across the life course. Such approaches may strengthen understanding of how multiple environmental and social exposures jointly influence health and inform future policy and intervention efforts.