The purpose of the current study was to examine whether the rate and type of parent-reported homework completion is associated with parent-report of child behavior outcomes, number of sessions to master parental skills as measured by therapist observation, and length of treatment in Parent–child Interaction Therapy (PCIT). Sixty-two parent–child dyads (primary caregiver: Mage = 36.35 years, female 95.20%, 81.60% White, 59.57% Hispanic; child Mage = 4.22 years; child gender male 64.50%) who completed PCIT were included in the study. A within-subjects hierarchical regression statistical design was used to examine the impact of parent report of homework completion on treatment processes and outcomes. A higher rate of self-reported homework completion was predictive of parental mastery of skill acquisition in fewer sessions and treatment completion in fewer sessions. Parent report of homework completion rate was not related to changes in child disruptive behavior after controlling for child behavior at baseline. Current study findings reinforce the importance of having parents regularly practice PCIT skills outside of session in order to decrease treatment length and facilitate the acquisition of parenting skills, which may reduce family burdens associated with attending a weekly treatment.