Since the beginning of child treatment, therapists of various orientations have struggled with whether, when, and how to set limits during therapy. Debate centers on the extent to which therapy should impose external limits or develop internal constraints on behavior and whether following one of those courses negatively impacts the other. This paper explores how that determination can be made through the same principles underlying other interventions: an understanding of the complex dynamics of the case; the developmental level of the child; the meaning, purpose, and communication of the offensive behavior; and the dynamics in the transference and countertransference. What happens before, during, and after a limit is set functions as significant therapeutic moments that require their own attention and response, including at times interpretation or reparation. The understanding of underlying dynamics and how they are addressed is what makes limit setting a therapeutic tool that deepens and furthers the therapy rather than simply a management technique.