Abstract Objective: To determine the factors associated with the nutritional status of children under 5 years of age in Guinea between 2005 and 2018. Design: Data from the 2005, 2012 and 2018 Guinea Demographic and Health Surveys (DHS) were used for this study. Three anthropometric indicators (stunting, underweight and wasting) were assessed according to the 2006 WHO Child Growth Standards and analysed according to the year, the characteristics of the household, the child and the mother using multivariate logistic regression. Setting: Data were collected in the capital Conakry and in the seven administrative regions of Guinea. Participants: The study included children under 5 years of age for whom height and weight were available: 2765 (DHS-2005), 3220 (DHS-2012) and 3551 (DHS-2018). Results: Analysis of the data from the three surveys showed that children living in rural areas were more likely to be stunted than children living in urban areas (OR = 1·32, 95 % CI (1·08, 1·62)). Similarly, the children from middle, poor and the poorest households were more likely to be stunted and underweight than children from richest households. The chance to stunting increased with age in the first 3 years. However, the chance to wasting decreased with age. Children in all age groups were more likely of being underweight. Children of thin mothers were more likely to be both wasted (OR = 2·0, 95 % CI (1·5, 2·6)) and underweight (OR = 1·9, 95 % CI (1·5, 2·3)). Conclusion: The implementation of targeted interventions adapted to the observed disparities could considerably improve the nutritional status of children and mothers.