Background: Worldwide, it is estimated that 52.9 million children <5 years of age experience delayed psychomotor development, which is associated with multiple factors. Our primary objective is to evaluate whether there is an association between supplementation with Vitamin A, Iron, and Micronutrients and Adequate Psychomotor Development in children aged 9–36 months at the national level in Peru. Methods: The study was an observational, analytical, cross-sectional study based on the secondary analysis of the Demographic and Family Health Survey databases from 2018 to 2020. The independent variables include the consumption of Vitamin A, Iron, and Micronutrients. The dependent variables encompass Motor Development in children aged 9–18 months, Psychological Development in children aged 9–18 months, and Psychological Development in children aged 19–36 months. Results: The study incl...