Faltering growth (FG) is a problem regularly seen by clinicians in infants and young children (<2 years of age). It can occur due to non-disease-related and disease-related causes and is associated with a wide range of adverse outcomes, including shorter-term effects such as impaired immune responses and increased length of hospital stay, and longer-term consequences, including an impact on schooling and cognitive achievements, short stature, and socioeconomic outcomes. It is essential to detect FG, address underlying causes and support catch-up growth where this is indicated. However, anecdotal reports suggest misplaced fear of promoting accelerated (too rapid) growth may deter some clinicians from adequately addressing FG. An invited international group of experts in pediatric nutrition and growth reviewed the available evidence and guidelines on FG resulting from disease-related and non-disease-related effects on nutritional status in healthy term and small for gestational age infants and children up to the age of 2 years in low-, middle-, and high-income countries. Using a modified Delphi process, we developed practical consensus recommendations to provide clarity and practical recommendations for general clinicians on how FG should be defined in different young child populations at risk, how FG should be assessed and managed, and the role of catch-up growth after a period of FG. We also suggested areas where further research is needed to answer remaining questions on this important issue.