Purpose The objective of this study was to build and validate a scale to analyze the knowledge, attitudes and practices on the sustainability of university students. Design/methodology/approach Psychometric validation was carried out using the criteria of internal consistency, reliability, discriminant power, content validity and predictive validity. Findings The KAP scale designed in this study demonstrated excellent psychometric properties and is apt for evaluating knowledge, attitudes and practices in university students. Originality/value Transitions toward sustainability require changes in knowledge, attitudes and practices (KAP) related to sustainability, making it necessary to have tools that support educational interventions for sustainability that tend toward a generation of changes in the decisions and behavior of people. In that sense, a KAP scale can be a useful tool to support these interventions. However, studies that use validated scales are scarce.