This dataset supports a publication on the determinants of infant growth in a birth cohort in the Nepal plains.This study aimed to identify the determinants of infant growth in terms of length-for-age z-score (LAZ) in a birth cohort (n=602) in the plains of Nepal. Children were enrolled within 72 hours of birth and followed-up every 28 days until they were 2 years. We fitted mixed-effects linear regression models controlling for multiple measurements within individuals to examine the impact of household and maternal factors, feeding practices and infection on infant LAZ. We conducted separate analyses for the age periods 0-6 months (exclusive breastfeeding period) and 7-24 months (complementary feeding period) to check whether the importance of determinants differed by child age.The data are useful to those seeking to understand the factors associated with longitudinal changes in nutritional status in children from birth to 2 years in the plains of Nepal.