This article reviews the development of a new measure to assess children's perceptions of intergenerational boundary violations in families. The Boundary Violations Scale is a theoretically derived instrument consisting of 12 items. Principal components analysis using data from 119 young adolescents from diverse ethnic backgrounds (i.e., 56% Hispanic and 44% non-Hispanic) revealed three factors (promoting maturity, forming coalitions, and communicating as peers) that are consistent with the behavioral manifestations of this construct as posited by structural family theory. The validity of the measure was supported by significant correlations with theoretically relevant measures of family processes and child adjustment as reported by children and their mothers.