Standardised classification system for bespoke thermoplastic ankle foot orthoses

•Standardised terminology for AFOs is critical, without these, there may be serious negative consequences.•No other classification system for bespoke thermoplastic AFOs currently exists. .•The proposed classification system based on AFO design and function has an excellent inter- and intra-observer agreement.•The classification system will allow comparisons between different bespoke thermoplastic AFOs and allow meta-analyses.•This classification is essential for evidence-based treatment of pathologies requiring bespoke thermoplastic AFO intervention.