This study aimed to develop the Thai school lunch planning program using nutrient profiling (NP). The intention was to create a user-friendly tool that aids teachers in preparing nutritionally balanced school lunch menus. The Thai school lunch planner was developed by gathering 53 popular lunch menus from a school lunch outsourcing company in Bangkok. Menus were grouped into ten categories based on food characteristics and cooking methods. Then, menus were graded according to their energy and 13 nutrients using NP criteria as ‘grade A’ (score >16), ‘grade B’ (scores 12-16), and ‘grade C’ (score <12), and menu category codes were created. Lunch sets were matched across the menu category codes and based on the two formats of school lunch standards. Finally, lunch sets were graded based on energy and 13 nutrient contents using NP criteria, with cut-off macronutrients set at 30% of Thai DRI 2020. Regarding the two formats of school lunch standards, this study found 63 uniquely matched patterns, with the possibility of forming 5,160 lunch sets. Lunch pattern format 1 had 57 patterns and 5,085 menu sets, of which 2,706 menu sets met 30% of the Thai DRI macronutrient requirement. The lunch pattern format 2 could create up to 75 sets from six patterns. Thirty-seven menu sets (49.3%) met the 30% Thai DRI macronutrient requirement. NP could be a valuable alternative for planning school lunch sets to guarantee high-quality and nutritious meals. This technique can be combined with the existing school food menu guidelines. Teachers, with or without basic nutrition knowledge, can find this strategy relatively user-friendly. Even though this technique is suitable for primary schools that serve two side dishes, schools serving one side dish can apply it by increasing the portion of the side dish.

Childhood nutrition is fundamental to children’s growth and learning, yet recent national data indicate 13.3% of Thai children aged 6–14 years have overweight and 15.2% have obesity despite nationwide School Lunch and School Milk Programmes. This qualitative study examined how parents and school personnel perceive their roles, challenges, and collaboration in promoting healthy eating among pupils in three public schools in Chiang Mai. Using purposive recruitment, 16 mothers and 10 school personnel (seven teachers and three directors) participated in parent focus groups and individual interviews; data were transcribed in Thai and analysed thematically. Three themes were identified: fragmented role division within and between home and school food actors, varied meal-management models under constrained staff and budgets, and food procurement challenges restricting healthy options. Parents described limited opportunities to contribute views on school food practices and primarily discussed supporting children’s eating at home, whereas school personnel described a broad mandate encompassing menu planning, procurement, and problem-solving with insufficient guidance and institutional support. Both groups identified children’s preferences for unhealthy snacks and the surrounding food environment as challenges, but emphasised different forms of support. While parents suggested that improved home–school communication could be beneficial in similar settings, school personnel highlighted structural support and clearer policy direction.