Objectives: This study investigated changes in family systems as a result of Integrated Family Play Therapy with families of ADHD children. Methods: Ten mothers of ADHD children from two child psychiatry clinics in Seoul participated. Integrated Family Play Therapy was conducted by using a meta-model of Structural Family Therapy, Strategic Family Therapy, and Solution Focused Family Therapy. Transcriptions of in-depth, post-therapy interviews with the mothers were analyzed. Results: Positive changes resulted from the play therapy in each family member, family subsystem interactions, and the whole family system. The therapeutic factors of the play therapy were found to be a) family plays, b) structured time setting for dialogue and play, c) setting rules in the therapy sessions, d) emotional support and acceptance of family members, e) respect for the children's emotions and opinions, f) providing a model for solving conflicts, g) exploring of children’s resources, h) creative plays, and i) feedback on the family interaction. Conclusions: The therapeutic factors of Integrated Family Play Therapy proved to be influential on intrapersonal changes as well as interpersonal changes, which led to positive changes in family systems.