Externalizing disorder refers to a group of behavioral and emotional problems in young people. Interventions and treatment are necessary for these children. This study aimed to compare the effectiveness of child-centered playtherapy and filial therapy in reducingexternalizingproblems inchildren. To achieve this purpose, atfirst, using the Eyberg Child Behavior Inventory (Eyberg, Ross, 1978) 300children who were7-8years of agewere tested and amongthosewith highscores, 12 children who obtained the highest score of externalizingscale of the child Behavior Checklist (CBCL; Achenbach and Rescorla, 2001) were selectedas the sample group. Children were randomly assigned to intervention groups: child-centered play therapy and filial therapy. In child-centered play therapy group, each child participated in 16 sessions play therapy (each lasted 45 minutes) and in filial group, mothers received eight group sessions. In child-centered play therapy, mothers completed CBC Lagain at the end of forth, eighth, twelfth and sixteenth and in filial therapy, they did this at the end of second, fourth, sixth and eighth sessions. Repeated measures ANOVA revealed significant difference between play therapy and filial therapy in decreasing externalizing problems and filial therapy was more effective. Then, filial therapy can be considered suitable alternative for child-centered play therapy that reduces child’s problems in shorter time and thereby increases the effectivenessof treatment.