This research describes the proportion of children in four low- and middle-income countries with adequate dietary practices at 6, 12, 18 and 24 months of age and how these practices changed over time using the World Health Organisation and UNICEF's infant young child feeding (IYCF) indicators. The associations between the IYCF indicators and anthropometric z-scores from 6 to 24 months, and between the IYCF indicators and the family care indicators (FCIs) at 24 months are described. This was a longitudinal study of offspring from participants in the Women First Preconception Maternal Nutrition Trial conducted in Sud-Ubangi, Democratic Republic of Congo; Chimaltenango, Guatemala; Belagavi, North Karnataka, India; and Thatta, Sindh Province, Pakistan. The frequency of the minimum dietary diversity (MDD), minimum meal frequency (MMF), and minimum adequate diet (MAD) increased between 6 and 24 months, but even at 24 months MAD remained below 50% at all sites. MDD (β = 0.12; 95% CI = 0.04-0.22) and MMF (β = 0.10; 95% CI = 0.03-0.17) were positively associated with length-for-age z-score at 24 months. All IYCF indicators were positively associated with mean total FCI score: MDD (proportion ratio [PR] = 1.04; 95% CI = 1.02-1.07), MMF (PR = 1.02; 95% CI = 1.01-1.04), MAD (PR = 1.05; 95% CI = 1.02-1.08). Although there are multiple barriers to young children having an adequate diet, our results support a positive association between familial interactions and improved IYCF feeding practices.