IntroductionEnvironmental toxicants such as chemical pollution have an enormous impact on the health of people and the planet. Emerging findings suggest that non-communicable diseases are linked to early and chronic environmental exposures. However, the rapid globalisation in developing countries, environmental change and the emergence, spread, persistence and severity of infectious diseases are not yet well understood. The aim of this study is to understand which environmental toxicants are commonly associated with infectious diseases in low-income and middle-income countries (LMICs).Methods and analysisA total of four electronic databases, MEDLINE through PubMed, Scopus, Web of Science and CENTRAL (the Cochrane Library) be searched to identify relevant studies and will be screened by two independent reviewers. The Cochrane risk of bias (ROB) tool for randomised control trials (RCTs) and ROB assessment tool for non-randomised studies for non-RCTs will be used to assess the ROB. A meta-analysis will be used to determine the pooled effect if we find out the included articles have similar environmental exposure, participant groups, study design and outcome measures. A narrative synthesis of the findings will be provided, along with summaries of the intervention effect. Heterogeneity between the studies will be assessed, and sensitivity analysis will be conducted based on study quality.Ethics and disseminationFindings will be summarised in a single manuscript. This review attempts to explore the pivotal role of environmental toxicants in predisposing, developing, persistent and severity of infectious diseases in LMICs. Findings from this study will highlight the effects of individual environmental toxicants’ role on infectious disease outcomes for the early prevention and limit toxic exposure to guide individual, community, and occupational health policy for future strategies.PROSPERO registration numberCRD42021274359.