Early years caregivers can play a key role in young children’s eating and the prevention of childhood obesity. The UK National Diet and Nutrition Survey (NDNS) is a large representative survey collecting detailed food and nutrition consumption data. Using these data, the aim of this study was to investigate the relationship between dietary intake of preschool children in the UK aged 2 to 4 years and accompanying adult/s. Nutrition consumption data from 1218 preschool children from years 1 to 8 of the 2008–2016 NDNS were accessed. Dietary data were captured using 3 or 4 day estimated food diaries. Regression analyses revealed significant differences in consumption when children were not accompanied by their parents. Compared with when children were with parents, children consumed significantly more energy dense meals (0·32 kJ/g, 95% CI 0·1–0·6 kJ/g), energy (62 kJ/g, (95% CI 27–97 kJ)) Na (19 mg, (95 % CI 6, 32)), added sugars (0·6 g, (95 % CI 0·1, 1·1)), vegetables (3 g, (95 % CI 1, 4)), total grams (12 g, (95 % CI 3, 21)) and saturated fat (0·2 g, (95 % CI 0·1, 0·4)) per eating occasion when accompanied by wider family. When children were accompanied by a formal childcare provider, they consumed significantly lower energy dense meals (−0·9 kJ/g, (95% CI −1·4 – −0·3 kJ/g)), less added sugars (−1·6 g, (95 % CI −2·4, −0·8)) and more fruit (12 g, (95 % CI 3, 21)) per eating occasion than when they were with their parents. The results demonstrate that non-parental caregivers might be an important target to promote healthy eating in young children. Further research is needed to establish which caregivers would benefit most.