Objective: The purpose of the study was to discover whether tomato consumption in elementary- and middle-school students could be increased through a school lunch programme developed by agricultural high-school students acting as peer educators. Design: The high-school lunch programme included the process of growing tomatoes and providing a newsletter on school lunches to elementary- and middle-school children. Agricultural high-school students were trained as peer educators. Setting: Six hundred and thirty-one students at 16 schools in Hokkaido, Japan, participated in the programme. Method: The evaluation survey items comprised questions about taste preference, eating motivation, and behaviours related to the high-school lunch programme and the usual school lunch. The analysis provided a comparison between a group of students who ate more tomatoes after the programme and a group who showed no change in eating preferences, and revealed factors affecting the increase in tomato consumption. Results: In all, 17% of the students started to eat more tomatoes after the programme than they had eaten previously. Among the students who ate more tomatoes, the ratio of answers on the choices "Tomatoes were delicious", "I request high-school lunch again", and "I want to eat high-school tomatoes at home" was significantly higher than that among other students whose tomato intake did not increase. The most important factors affecting increased tomato consumption were "students' tomatoes were delicious". Conclusion: A school lunch programme developed by agricultural high-school students may be effective for increasing vegetable consumption in elementary- and middle-school students.