Nutritional geometry (NG) is a novel dietary analysis approach that considers nutrient balance, rather than single nutrient effects, on health and behaviour. Through NG, recent animal experiments have found that lifespan and reproduction are differentially altered by dietary macronutrient distribution. Epidemiological research using NG reports similar findings for human ageing. Yet, the relation of macronutrient balance to human reproduction, especially reproductive maturation, remains undefined. We studied the impact of childhood macronutrient intake on pubertal maturation, by applying NG to an Australian longitudinal adolescent dataset. Food records, collected at age 8 years from 142 pre-pubertal children (females, 92; males, 50), were analysed for absolute energy, percentage energy and energy-adjusted residuals from protein, carbohydrate and fat. Pubertal stage change (assessed at 8, 13 and 15 years) was modelled to obtain individual mathematical estimates of pubertal timing and tempo. Timing of menarche was recorded. The association of macronutrients to pubertal timing/tempo was assessed via NG, involving generalised additive models and heat maps to aid interpretation. Results showed lower dietary protein (relative to carbohydrate and fat) in girls consistently predicted earlier pubertal timing and menarche, and was related to faster pubertal tempo (all P < 0·05). No significant associations were identified in boys for both timing and tempo. Results suggest a role of non-protein macronutrients in facilitating female maturation; corroborating feeding and reproductive behaviour patterns observed in earlier NG studies of primates. Application of NG to other adolescent datasets is required to confirm the present findings. Such work would advance understanding of how nutrient balance shapes human development and health.