Objectives: Healthy and sustainable eating should be encouraged in children. This study aimed to create, apply and evaluate the effectiveness of a specially designed, school-based educational programme to promote healthy and sustainable eating in children. Design: Pilot, school-based educational intervention, aimed at promoting health and sustainable eating patterns in children. Setting: Four schools (two primary schools and two kindergartens) in Attica, Greece. Method: The 3-month, pilot intervention consisted of a teacher training session, an educational package (11 teaching sessions, 1 session/per week), 3 separate parents and teachers' educational sessions, and 2 teacher feedback meetings. In total, 290 children (intervention group n = 230, control group n = 60) aged 5-11 years old from four schools in Attica, Greece, participated in the study. Parents completed a specially designed questionnaire before and after the intervention, assessing children's anthropometric characteristics, children's adherence to a Mediterranean Diet (MD) and physical activity levels, together with usual eating and food waste behaviours in the household. Results: Children's adherence to a MD was not significantly affected by the educational intervention. However, there was a significant increase in children's fruit consumption, with 48% of the children eating at least two portions of fruit per day after the intervention. With respect to the food sustainability behaviours of the household, the intervention group threw away less food and, in particular, fewer fresh fruit and less bread, following the intervention. Conclusion: There is evidence that the educational programme can positively affect certain healthy eating behaviours in participating children.