This study aimed to deepen the understanding of the influence of the properties of school uniforms that may contribute to discomfort and irritation for children with sensory overreactivity. The specific objectives were (a) to identify the difficulties that children with sensory overreactivity experience when wearing a school uniform and (b) explore possible adaptations of the school uniform that can reduce the discomfort and irritation caused by the uniform. In this exploratory, qualitative study, four focus group interviews were conducted with a total sample of 16 participants. Mothers and occupational therapists that live and work with children with sensory overreactivity participated in this study. During thematic analysis, three themes emerged as important to understand the discomfort caused by a school uniform: textiles, design, and construction. This study contributes to the literature on school uniforms and the sensory aspects of clothing. Guidelines for parents are presented and future research possibilities are discussed.