Low socioeconomic status (SES) is a risk factor for unpreparedness for formal school entry. However, it is unclear how specific SES domains or factors related to SES, such as maternal caregiving style or child biological stress regulation, uniquely contribute to a child's academic competency. We examined the relation between early biological stress, SES, and caregiving style with the academic competency domain of school readiness in a preschool-age sample (N = 91) using multidimensional measures of SES, measures of maternal behavior, child hair cortisol concentrations, and diurnal salivary cortisol. We also investigated which correlates uniquely contribute to academic competency as indexed by the Bracken School Readiness Assessment and the NIH Picture Vocabulary Test. Higher cumulative biological stress, indexed through hair cortisol concentrations, was related to lower scores on both measures. Poor biological stress regulation, indexed by a flatter diurnal cortisol slope, was related to lower receptive vocabulary. More sensitive maternal behaviors and measures indicating higher SES were related to better performance in both academic competency measures. Of these significant associations, maternal intrusion and parental education uniquely contributed to pre-academic skills beyond other measures, whereas maternal structuring and parental education uniquely contributed to receptive vocabulary. These results provide new evidence that biological stress is related to academic competency in early childhood and demonstrate the importance of structured, non-intrusive parenting when preparing children for long-term academic success. (author abstract)