Parent involvement in the treatment of childhood disruptive behavior problems is a critical component of effective care. Yet little is known about the amount of time therapists are involving parents in treatment and factors that predict therapists' efforts to involve parents in routine care. The purpose of this study is to examine therapists' within-session involvement of parents in community-based outpatient mental health treatment. The data are from a larger longitudinal observational study of psychotherapy for children ages 4-13 with disruptive behavior problems and include videotaped psychotherapy sessions coded for the therapeutic strategies delivered as well as measures of child, parent/family, and therapist characteristics at baseline. Parent involvement is defined as the proportion of time in the session that therapists direct treatment strategies towards parents. Results indicated that therapists directed treatment strategies towards parents an average of 44% of the time within a session. Multilevel modeling was used to examine client-level (child, parent, and family functioning) and provider-level (therapist experience and background) predictors of parent involvement. Therapists involved parents more when the child had higher levels of behavior problems, when the parent reported higher levels of internalized caregiver strain, and when the therapist was more experienced. The results highlight potential areas to target in efforts to increase parent involvement, including training less experienced therapists to increase their focus on directing strategies towards parents.