This study examined developmental timing of brain lesion effects on children's attention skills. The sample of 138 children, 10-16 years at assessment, were grouped based on developmental timing of brain lesion: (1) Congenital; (2) Perinatal; (3) Infancy; (4) Preschool; (5) Middle Childhood; (6) Late Childhood. Children with lesions in infancy or earlier demonstrated global attention problems, while children with lesions in middle childhood performed closer to normal expectations. This pattern of results was particularly evident for encoding and shifting attention. Findings highlight vulnerability of the immature brain to lesions and identify critical periods in development for attention skills.