Schools and early years settings provide an opportunity to promote healthy and sustainable food, but standards and guidance in England focus predominantly on nutritional quality. The present study estimated greenhouse gas emissions (GHGE) of school lunches provided for children attending school nurseries, including comparison between meal options. Menus, recipes and portion weights for lunches provided for 3-4-year-old children attending nine school nurseries were collected daily for one week. GHGE for each food and recipe were calculated using Foodprint functionality of Nutritics software. GHGE were calculated for each menu option (main, vegetarian, jacket potato and sandwich) provided in each school, and for meals with and without meat/fish. In total, 161 lunches including 273 foods were analysed. Median GHGE across all meals was 0.53 kgCO2e (i.e. kilograms of carbon dioxide equivalent) per portion, with significantly higher GHGE associated with main meals (0.71 kgCO2e per portion) compared to all other meal types (0.43-0.50 kgCO2e per portion; p < 0.001) which remained after adjustment for meal size and energy density. Red meat-based meals were highest in GHGE (median 0.98 kgCO2e per portion and 0.34 kgCO2e per 100 g) and meals containing any meat/fish were significantly higher in GHGE (median 0.58 kgCO2e per portion) than vegetarian meals (median 0.49 kgCO2e per portion) (p = 0.014). Meals with higher adherence to the nutrient framework underpinning the early years guidelines had significantly higher GHGE than meals with lower adherence (p < 0.001). The results were comparable to previous estimates of school lunch GHGE and highlight variation by meal option. Consideration of GHGE alongside the nutritional quality of lunches by caterers could support provision of healthy and sustainable lunches.