Objective To evaluate gait dynamics and self-reported foot-related disability before and after treatment with intraarticular corticosteroid injections (IACI) in children with juvenile idiopathic arthritis (JIA) and foot involvement, and determined whether children with polyarticular and oligoarticular disease responded similarly to IACI treatment. Methods Forty-three children (35 girls and 8 boys) with JIA were consecutively recruited (mean ± SD age 11.1 ± 4.2 years, mean disease duration 4.5 ± 3.6 years). Sixty-five percent were diagnosed with polyarthritis. All children received IACI treatment for ankle and/or foot joint synovitis. Fifty-eight percent received additional injections in the knee and/or hip joint. Forty healthy children, matched by age and sex, comprised the control group. Gait dynamics and foot-related disability were assessed before IACI treatment and at 3 weeks and 3 months following the injections. Results Foot-related disability and inflammatory joint symptoms improved following treatment. Gait dynamics were compromised before treatment and did not improve following treatment (mean ± SD nondimensional walking speed 0.49 ± 0.05 in the control group; 0.44 ± 0.07 in the JIA group pretreatment; 0.43 ± 0.10 in the JIA group 3 weeks following treatment; and 0.43 ± 0.07 in the JIA group 3 months following treatment) (P = 0.001 in controls versus pretreatment JIA group, P = 0.45 JIA over time). Mean ± SD ankle power was 3.81 ± 0.67 in the control group; 3.01 ± 1.19 in the JIA group pretreatment; 3.19 ± 1.30 in the JIA group 3 weeks after treatment; and 3.22 ± 1.03 in the JIA group 3 months after treatment (P < 0.001 in controls versus pretreatment JIA group, P = 0.51 JIA over time). The ankle power to hip power ratio was reduced (P = 0.01 in controls versus pretreatment JIA group), indicating a power shift from the ankles to the hips, which was more prominent in children with polyarthritis. Conclusion As a result of IACI treatment, improvements were found in self-reported foot-related disability and inflammatory joint symptoms, but gait dynamics were unchanged. Children with polyarticular disease and those with greater self-reported walking difficulties prior to IACI treatment demonstrated worse outcomes, and children in these groups should be monitored carefully after treatment.