With this article we would like to contribute to the elaboration and clarification of the concept of filial maturity. We first roughly outline how the concept has been used during the past 30 years to describe the nature and quality of the adult child-parent relationship. The concept is analysed in more detail. We argue that filial maturity can be placed in a developmental psychological perspective. This means that it has to be conceived as a specific maturity in the filial role and that some arguments can be given to explain the developmental psychological character of the concept. In view of the theoretical and clinical applicability of the construct we prefer to consider filial maturity as a non-age-graded developmental task within the context of filial care of adult children for their aged parents. Within this context of parent care we propose a (new) definition of the concept and differentiate it from other related constructs. Our definition highlights three important dimensions which refer to the way the adult children engage in the relationship with their parents: (a) they behave in an empathetic and responsive way in the intergenerational relationship, without role-reversal, (b) they take care of their aged parents without loosing their own autonomy, and (c) they respect their parents in their autonomy and enduring parental role.