Objective: To describe and quantify the magnitude and distribution of stunting, wasting, anaemia, overweight and obesity by wealth, level of education and ethnicity in Ecuador.Design: We used nationally representative data from the 2012 Ecuadorian National Health and Nutrition Survey. We used the Multidimensional Poverty Index (MPI) as a proxy of wealth. The MPI identifies deprivations across three dimensions (health, education and standard of living). We defined education by years of schooling and ethnicity as a social construct, based on shared social, cultural and historical experiences, using Ecuadorian census categories.Setting: Urban and rural Ecuador, including the Amazon rainforest and the Galapagos Islands.Participants: Children aged <5 years (n 8580), adolescent women aged 11-19 years (n 4043) and adult women aged 20-49 years (n 15 203).Results: Among children <5 years, stunting and anaemia disproportionately affected low-wealth, low-education and indigenous groups. Among adolescent and adult women, higher rates of stunting, overweight and obesity were observed in the low-education and low-wealth groups. Stunting and short stature rates were higher in indigenous women, whereas overweight and obesity rates were higher in Afro-Ecuadorian women.Conclusions: Malnutrition differs significantly across sociodemographic groups, disproportionately affecting those in the low wealth tertile and ethnic minorities. Rates of stunting remain high compared with other countries in the region with similar economic development. The effective implementation of double-duty actions with the potential to impact both sides of the double burden is urgently required.