Research has indicated that filial therapy, an approach in which parents conduct play sessions with their young children, has strong effects on the participating parents and children. As a result, some have speculated that filial therapy improves the family system; however, minimal research exists to support this claim. Using a single-case, time-series design, I examined the impact of child parent relationship therapy (CPRT), a filial therapy approach, on the functioning of 8 diverse families (two-parent, biological children = 4; two-parent, adopted children = 3; single-parent, biological children = 1). 15 parents and 17 children (male = 15, female = 17) participated in the study. All but 1 parent was Caucasian. The children were more ethnically diverse (Caucasian = 5, Hispanic/Caucasian = 5, Hispanic = 3, Asian = 2). Parents’ ages ranged from 29 to 49 and children’s from 2 to 13. Results from simulation modeling analyses (SMA) indicated that 6 of 7 families experienced a statistically significant improvement in their targeted areas of family functioning, and the average effect size was moderate. Results from self-reported measures indicated that 7 families experienced notable improvements in family satisfaction, 4 in cohesion, 3 in communication, and 1 in flexibility. Data from an observational …