Home-packed foods (foods which are prepared and/ or packed at home) hold the potential to improve school food behaviours of Australian secondary school students since most students (83%) bring home-packed lunches to eat at school (1). However, Australia lacks in-depth exploration of the home-packed foods of Australian secondary school students. As such, this study aimed to assess food-group diversity and estimate the energy contribution of core food groups and discretionary foods using lunchbox photographs. Lunchbox photographs were collected as part of an online survey on ‘what foods do secondary school students take to school’, which was conducted in 2024-2025 with parents of secondary school students across Australia. Parents were asked to submit up to three photographs of their child’s lunchbox, taken on three different days over a school week, accompanied by a brief description about the foods included in the photograph and their approximate quantity. Each food item in the lunchboxes was categorised into one of the five core food groups or as a discretionary food according to the Australian Guide to Healthy Eating (2). Foodworks Online nutrition analysis software was used to estimate the energy (kJ) of food items. A total of 112 photographs of home-packed foods were collected from 53 parents. The majority of lunchboxes contained fruits (93%), grain (cereal) foods (81%) and vegetables and legumes/ beans (80%), whereas milk and alternatives (47%) and meat and alternatives (37%) were less commonly present. Only 14% of lunchboxes contained all five core food groups. Most (85%) lunchboxes included at least one discretionary food item (not including discretionary spreads), and 56% of them contained two or more discretionary food items. The mean total energy from home-packed foods was 3619.7 ± 1581.7 kJ. Discretionary foods (without discretionary spreads) contributed the highest energy (38%), followed by grain (cereal) foods (23%), fruits (11%), milk and alternatives (9%), meat and alternatives (8%), vegetables and legumes/ beans (5%) and ‘leftovers/ mixed dishes’ (foods that could not be classified under the main food groups) contributed to 2%. These findings show milk and alternatives and meat and alternatives are underrepresented in school lunches and the energy contribution from discretionary foods exceeded the energy contribution from any individual core food group. This highlights the need for strategies to improve the nutritional quality of the home-packed foods that adolescents take to school. Such strategies may include offering healthy lunchbox recipe resources, lunchbox checklists aligned with the Australian Guide to Healthy Eating, healthy lunchbox assembling activities/games and lunchbox demonstrations.