Objective: To describe high-dose biologic use when treating juvenile idiopathic arthritis (JIA). Methods: Patients with JIA enrolled in the Childhood Arthritis and Rheumatology Research Alliance Registry and treated with a biologic after enrollment were eligible. We described the frequency of high-dose biologic use and characteristics of patients receiving high-dose biologics. We used regression modeling to compare 6-month outcomes (using disease activity measures) between those who increased their biologic from standard to high dose (high-dose group) to those who initiated and remained on standard dosing (no-change group), and to those who switched biologic agents (biologic-switch group). We also compared serious adverse events (SAEs) between groups. Results: A total of 5,352 patients with JIA were treated with biologics following enrollment; 1,080 (20%) had ever received a high-dose biologic. There were no significant differences in outcomes between the high-dose group and the biologic-switch group; both improved disease activity measures, including the clinical Juvenile Arthritis Disease Activity Score 10 (–3.53 and –3.95, respectively; P = 0.68). Although the SAE rates in the high-dose group and the biologic-switch group were numerically higher than the no-change group, the event rates were similar, and neither rate was significantly higher than in the no-change group (unadjusted incident rate ratio 2.5 [95% confidence interval (95% CI) 0.7–8.5] and 1.8 [95% CI 0.7–4.6], respectively). Conclusion: Dosing escalation appears to be a reasonable choice to improve disease control, but large, prospective, randomized studies evaluating specific biologic agents are needed.