Undernutrition in children remains a major global health issue and the prevalence of undernutrition in children under age five in the Democratic Republic of the Congo (DRC) is among the highest in the world. Both biological and socioeconomic factors contribute to undernutrition, and the literature reports an association between women's empowerment and lower rates of child undernutrition in sub-Saharan Africa. However, the relationship between women's decision-making power and child undernutrition is less understood. The objective of this study was to evaluate the association between women's decision-making power and stunting/wasting in their children under age five in the DRC. This study used cross-sectional data from the 2013-2014 DRC Demographic and Health Survey, from which a sample of 3,721 woman-child pairs were identified. Women were classified as having decision-making power in five decision-making dimensions if they participated in the decision either alone or jointly with their husband or partner or someone else. Child height-for-age and weight-for-height Z-scores were used to determine stunting and wasting, respectively, according to the World Health Organization Child Growth Standards. Multivariate regression analyses demonstrated that none of the five dimensions of decision-making power were associated with stunting or wasting in children. Further research that evaluates women's decision-making power with more detailed, relevant and context-specific measures is warranted to more accurately investigate women's decision-making power and undernutrition in children.