A large proportion of children are at risk of food insecurity during school holidays in the UK. The government-funded Holiday Activities and Food (HAF) programme provides free holiday clubs offering at least one healthy meal/day to eligible children and adolescents. This study aims at evaluating the nutritional quality of food provision at HAF holiday clubs, particularly hot/cold and vegetarian/non-vegetarian meals. Menu variants (n = 2759) from 49 HAF holiday clubs were assessed for adherence to School Food Standards (SFS) and their notional compositional quality, which was scored utilising a novel nutrient-based meal quality index. The median adherence to SFS across all available menus was 70% (IQR 59–79%). Overall, hot variants scored statistically higher menu quality scores than cold variants for both 5–11y (92.3 (80.7–102.7) vs. 80.4 (69.3–90.6)) and 11–18y (73.5 (62.5–85.8) vs. 58.9 (50.0–70.7)) criteria. Cold and hot menu variants tended to score differentially for quality sub-components. These findings highlight areas for potential future improvement in HAF holiday club provision with a tendency for food provision to appear less ideal for attendees for those aged 11–18. Ensuring that children from low-income households have access to a healthy diet is crucial to reduce UK health inequalities.