Children’s growth extends beyond gains in height and weight: it includes non-physical achievements. This paper reviews the research conducted by the International Union for Nutritional Sciences Task Force ‘Towards a Multidimensional Approach to Child Growth’, which developed a Multidimensional Index of Child Growth (MICG) framed within a capability- and human-rights- based conceptualisation of child growth across interconnected dimensions, including physical health, love and care, mental wellbeing, participation, autonomy, mobility, and safety. Qualitative research in Bangladesh and southeastern Tanzania informed the operationalisation of the MICG, showing that caregivers understand child growth as a multidimensional capability set distributed across children, caregivers, and households. Quantitatively, we prototyped the MICG using Young Lives Survey data from Ethiopia, India, Peru, and Vietnam. The MICG reveals patterns of deprivation not captured by anthropometric indicators alone, such as compounded shortfalls in education, mobility, and mental wellbeing among rural girls in Peru, despite similar physical growth profiles. Regression and quantile analyses indicate that community participation in the design of WASH programmes is associated with higher multidimensional achievements, particularly among the most deprived children. To bridge observed achievements and unrealised potential, we extend the MICG using a Bayesian stochastic-frontier approach to estimate context-specific capability distributions and identify children at risk of being left behind. Finally, we propose a spiderweb growth chart for monitoring multidimensional child growth, complementing WHO anthropometric charts. Overall, the MICG offers an equity-sensitive tool for evaluating nutrition interventions, strengthening child growth surveillance, and advancing the Sustainable Development Goal commitment to leave no child behind.