Allostatic Load (AL) is a construct that refers to multisystemic physiological dysregulations resulting from exposure to threats and deprivation related to chronic stress responses. While AL indexes can effectively predict negative health outcomes including cardiovascular diseases, reduced life expectancy, and impaired cognitive functioning, its measurement faces several methodological challenges, particularly in younger populations. Most research has focused on adults using a unidimensional approach, despite the large evidence demonstrating that systems involved in allostatic response undergo substantial developmental changes across the lifespan. To address this gap, this study examines the factorial structure of AL biomarkers and its association with contextual and individual variables in a sample of preadolescents using data from the Longitudinal Study of Australian Children (LSAC), a nationally representative household survey. The analysis includes data from 1874 preadolescents aged 11–12 years. Employing a data-driven approach, we randomly split the sample to first conduct an exploratory factor analysis with 12 biomarkers, which revealed a three-factor structure with 8 variables representing distinct physiological systems, subsequently validated through confirmatory factor analysis on the remaining sample. Results demonstrated acceptable fit for this three-factor solution (CFI =.94, RMSEA =.099, SRMR =.052). Additionally, regression analyses showed that both neighborhood disadvantage, pubertal developmental stage, sex and medication use differentially predicted AL factor(s). These findings highlight the value of a multidimensional approach to the AL construct and underscore the importance of examining developmental timing within their ecological context when studying physiological dysregulation resulting from repeated activation of stress response systems.