This study examined the effectiveness of solution-focused brief therapy (SFBT) on child well-being and family functioning outcomes for child welfare involved parents. A randomized controlled trial design was used to evaluate the effectiveness of SFBT as compared to treatment-as-usual in an outpatient substance abuse treatment center. Mixed linear models tested within and between-group changes using intent-to-treat analysis (N = 180). Hedges’s g effect sizes examined the magnitude of treatment effects. Both conditions reported improvements on the child well-being measures (Behavior Rating Inventory of Executive Function [BRIEF]-Parent Report and Child Behavior Checklist-School Age Form [CBCL-SA]) and family functioning measures (Adult-Adolescent Parenting Inventory [AAPI-2] and Center for Epidemiologic Studies-Depression [CES-D] Short Form) at posttest. While none of the between group analyses were statistically significant on either outcome domains, effect sizes did show improvements in the small to medium range for both groups. SFBT effect sizes for BRIEF subscales ranged from .024 to .267 and for control group ranged from .136 to .363. SFBT effect sizes on CBCL-SA subscales ranged from .059 to .321 and for control group ranged from .101 to .313. SFBT effect sizes on AAPI-2 subscales ranged from .006 to .620 and control group ranged from .023 to .624. SFBT effect sizes on CES-D measure were .428 and for control group were .317. Results show SFBT to be an effective intervention for helping parents around child well-being and family functioning outcomes similar to current empirically-supported therapies. SFBT provides a more strengths-based approach to help families improve family well-being and thus help improve their child’s well-being.