Backgrounds and Objectives: Little is known about how families respond to pediatric advance care planning. Physicians are concerned that initiating pediatric advance care planning conversations with families is too distressing for families. We examined the effect of family centered pediatric advance care planning intervention for teens with cancer (FACE-TC) advance care planning on families' appraisals of their caregiving, distress, and strain. Methods: In a randomized clinical trial with adolescents with cancer and their families conducted from July 2016 to April 2019 in 4 tertiary pediatric hospitals, adolescents and family dyads were randomly assigned at a 2:1 intervention/control ratio to either the 3 weekly sessions of FACE-TC (Advance Care Planning Survey; Next Steps: Respecting Choices; Five Wishes) or treatment-as-usual. Only the family member was included in this study. Generalized estimating equations assessed the intervention effect measured by Family Appraisal of Caregiving Questionnaire. Results: Families' (n = 126) mean age was 46 years; 83% were female, and 82% were white. FACE-TC families significantly increased positive caregiving appraisals at 3-months postintervention, compared with those in the control group (β = .35; 95% confidence interval [CI] 0.19 to 0.36; P = .03). No significant differences were found between groups for strain (β = -.14; 95% CI = -0.42 to 0.15; P = .35) or distress (β = -.01; CI = -0.35 to 0.32; P = .93). Conclusions: Families benefited from participation in FACE-TC, which resulted in positive appraisals of their caregiving for their child with cancer, while not significantly burdening them with distress or strain. Clinicians can be assured of the tolerability of this family-supported model.