Background:: The term “faltering growth” (FG) is widely used to refer to a slower rate of weight gain in childhood than expected for age and gender. The prevalence varies depending on the definition and the studied population. Early recognition is important when considering the short- and long-term consequences, which include reduced cognitive development and increased risk of morbidity and mortality. Summary:: The causes of FG are traditionally classified into being either illness- or non-illness-related. However, such a rigid classification does not acknowledge the fact that poor growth may be multifactorial. While many definitions for FG exist, a recent consensus document suggested that a drop of weight-for-height of 1 z-score warrants the consideration for FG. The nutritional assessment supports the calculation of energy and protein requirements, which should be tailored to the underlying cause.