Undernutrition in infants and young children is a global health priority while overweight is an emerging issue. Small-scale studies in low- and middle-income countries have demonstrated consumption of sugary and savoury snack foods and soft drinks by young children. We assessed the proportion of children 6–23 months of age consuming sugary snack foods in 18 countries in Asia and Africa using data from selected Demographic and Health Surveys and household expenditures on soft drinks and biscuits using data from four Living Standards Measurement Studies (LSMS). Consumption of sugary snack foods increased with the child's age and household wealth, and was generally higher in urban vs. rural areas. In one-third of countries, >20% of infants 6–8 months consumed sugary snacks. Up to 75% of Asian children and 46% of African children consumed these foods in the second year of life. The proportion of children consuming sugary snack foods was generally higher than the proportion consuming fortified infant cereals, eggs or fruit. Household per capita daily expenditures on soft drinks ranged from $0.03 to $0.11 in three countries for which LSMS data were available, and from $0.01 to $0.04 on biscuits in two LSMS. Future surveys should include quantitative data on the purchase and consumption of snack foods by infants and young children, using consistent definitions and methods for identifying and categorising snack foods across surveys. Researchers should assess associations between snack food consumption and stunting and overweight, and characterise household, maternal and child characteristics associated with snack food consumption.