Orthoses for children with flexible excess pronation are estimated to cost Australian parents millions of dollars per year; however, there is no high-level evidence that orthoses improve function or reduce pain. A randomized parallel, single-blinded, controlled trial of custom-made and ready-made orthoses was conducted in children between the ages of 7 and 11 years with bilateral flexible excess pronation. The diagnosis was based on calcaneal eversion and navicular drop. Outcomes included gross motor proficiency, self-perception, exercise efficiency, and pain. Measurements were taken at baseline, and at 3 and 12 months. Of the 178 children who participated at baseline, 160 continued to the end of the trial. After randomization, baseline characteristics were similar between the three treatment groups (custom-made, ready-made, and control). Statistical modeling demonstrated that although for most outcome measures there were statistically significant trends over time, none of the group comparisons were statistically significant. A sub-group analysis of those presenting with pain found no significant differences at 3 or 12 months. This study found no evidence to justify the use of in-shoe orthoses in the management of flexible excess foot pronation in children.