This paper expands upon the concept of “watched play,” a play state in which the mother silently but attentively watches her child play. The regulatory presence of the “watching mother” is introjected and internalized through the child's development of mental representations of mother's latently interactive presence, contributing to the development of self-regulatory mechanisms. By contrast, the consequences of failed “watched play” are disorganizing play disruptions which foster ambivalence and affect disregulation. The introjection of the “watching mother” during play contributes to the child's growing capacity to mentalize others' behaviors. Finally, “watched play” is consistent with the paradigm of the passive, albeit attentive analyst in both the adult and child analytic modes.