Aim <p>The climate crisis is the most critical public health threat of the twenty-first century. With the global food system and the future of our planet at risk in the face of environmental degradation, it is critically important to make sustainable, ecologically(eco)-friendly choices in our dietary habits. There are limited studies on sustainable eco-friendly nutrition in relation to children and adolescents, who are the determinants of the future. This study aims to develop a sustainable, eco-friendly nutrition (SEFN) scale .</p> Subject and methods <p>The SEFN scale was developed in these main steps: (1) creation of an initial item pool covering all aspects of sustainable eco-friendly nutrition, (2) review of items by experts, (3) application of the scale to a sample of 810 adolescents, (4) conducting psychometric analyses: construct validity was assessed using exploratory factor analysis (EFA) (<i>n</i>1 = 410) and confirmatory factor analysis (CFA) (n2 = 400), and (5) reliability. Content, item–test correlations, internal consistency, analysis of the difference between the upper–lower 27% groups, and test–retest reliability were examined.</p> Results <p>The newly developed scale obtained a 19-item, three-factor structure (awareness, sustainability, sensitivity).&#xa0;In the SEFNS, factor 1 (<i>α</i> = .89), factor 2 (<i>α</i> = .87) and factor 3 (<i>α</i> = .75) measured 57.83% of the total variance.&#xa0;The Cronbach's α value of the scale was 0.93.</p> Conclusion <p>The SEFN scale is a valid, reliable, and distinctive scale with regard to the measured feature, verified in a large Turkish sample. Using the SEFNS, public health researchers can measure children and adolescents' SEFN behaviors, test associated parameters, and use them to improve these behaviors.</p>