This study investigated the transmission of boundary dissolution (BD) in parent-child relationships from parental behaviors observed in early childhood to adolescent behaviors observed at age 13 and relations to adolescent psychosocial adaptation. The goals of the study are (a) to examine the developmental relation of early childhood BD to several measures of adolescent BD observed in 13-year-olds' behavior, (b) to compare two types of BD in adolescence and their associations with early childhood BD and subsequent psychosocial outcomes, and (c) to test the mediating role of adolescent BD between early childhood BD and later adolescent functioning. Participants were drawn from a study of 196 children followed since birth. Two forms of adolescent BD, role equalization and sexualized behavior, were observed during parent-adolescent structured interactions. Early BD childhood predicted observations of adolescent BD. Role equalization mediated relations to self-worth and externalizing problems. Implications regarding multiple types of adolescent BD are discussed.