Low academic achievements are predicted by early disadvantages. Because achievement gaps typically escalate with age, early efforts to prevent future academic disadvantages are called for. The current study examines whether exposure to structured pre-academic activities in Early Childhood Education and Care (ECEC) play a compensatory role for the early academic achievements in school (teacher ratings and screening tests of reading and math) of children who were at developmental (low receptive language), behavioral (high externalizing behavior and low effortful control) and socio-economic (low maternal education) risk in preschool. Using a sample of 934 children from the longitudinal Behavioral Outlook Developmental Study to examine between-school comparisons and within-school fixed effects models, findings suggest that preschoolers with externalizing behaviors may moderately benefit from structured pre-academic activities prior to school entry. However, it is concluded that this pre-academic boost is weak and may be limited to a short transition period from ECEC to school.