Advancing Environmental Sustainability Through Education: Development and Validation of a Scale to Measure School–Family Collaboration

School–family collaboration is a key factor in education for sustainability. However, rigorous evaluation of this relationship has been scarcely addressed from an empirical perspective. This study aimed to design and validate a scale to measure school–family collaboration in the field of environmental education. Based on a conceptual review, four key dimensions were defined: strategies and communication, family participation, impact on ecological habits, and implementation barriers. Content validation was conducted using the Delphi method with a panel of 15 experts. The scale was subsequently administered to 531 participants (312 teachers and 219 family members) from educational centers in various regions of Spain. Exploratory and confirmatory factor analyses confirmed a robust internal structure (Kaiser-Meyer-Olkin = 0.841; Comparative Fit Index = 0.945; Root Mean Square Error of Approximation = 0.062). Internal reliability, assessed through Cronbach’s alpha coefficient, was high (total α = .91), with consistent values across all dimensions (α > .80). The results demonstrate that the scale has structural validity and empirical reliability, making it a useful tool for future research, institutional evaluation processes, and the development of educational policies focused on socio-environmental co-responsibility.