Background Malnutrition is one of the main causes of death in children under 5 years of age and one of the most common factors threatening children’s life and health. Nutrition policy analysis and solving existing problems in children can reduce the effects of malnutrition. This study aimed to analyze the current policies of malnutrition prevention in children under five years of age in Iran. Method This study was conducted in 2017 to analyze policies using the "policy triangle framework". In order to examine the policy-making process, the Kingdon’s multiple streams model was used. A combination of two sampling methods, including purposeful and snowball sampling, was applied to select the interviewees. In relation to the implemented documents and policies, the country’s most important policies were selected based on the suggestions of policy makers as well as searching scientific databases and electronic portals. A data collection form was used to identify the current policies and documents and a semi-structured interview guide form was used for the interviews. The framework analysis and MaxQDA software were applied to analyze the data obtained from the interviews. Results The key factors affecting policies in Iran included the status of indicators as well as economic, social, structural-legal, policy and international factors. Among the most important policies and implemented programs, the following can be mentioned: growth monitoring, oral rehydration, breastfeeding, immunization, female education, family spacing, food supplementation, nutrition for children under five years of age, and control of nutritional deficiencies. Currently there is a need for a nationwide program and comprehensive document in the field of the nutrition in children under 5 years of age, which requires strengthening of the political process. Participants and stakeholders in nutrition-related policies for children under the age of five were divided into four categories of governmental, semi-governmental, non-governmental, and international organizations. Conclusion More attention should be paid to the shortage of some micronutrients, accurate implementation of breastfeeding programs, supplementary nutrition, fortification and supplementation programs for children and mothers, utilization of the advantages of each region and its resources, and better coordination between organizations and their policies, and finally strong incentives are needed to promote macro nutritional goals for children under five years of age.