Although there are no attendance or registration fees in the UK for publicly funded school education there are hidden costs in attending compulsory education. This article investigates one of the hidden costs: school uniform. We investigate the affordability of school uniform in Scotland, looking at what is required in school uniform policy (class uniform and Physical Education kit), the costs of uniform and to what extent the national minimum clothing grant makes uniform affordable for households on low incomes. For this research we use a unique national dataset of the school uniform policies of all 357 publicly funded secondary schools in Scotland and responses to Freedom of Information requests sent to all local authorities (n = 30). From analysis of the uniform policies and the requirements and application processes for the national minimum clothing grant we are able to draw together recommendations for the Scottish Government, local authorities and schools. We also found a compelling need for detailed data collection on how much it costs to clothe children for a whole school year.