Background: Very few studies exist in Chile about the relationship between the level of healthy eating and nutrition knowledge of mothers and their children’s nutritional status. Objetive: To determine the relationship between the nutritional status of Grade 4 schoolchildren from subsidized schools in San Carlos, Chile, and their mothers’ income, healthy eating and nutrition knowledge, and perception. Materials and Methods: Analytical cross-sectional study with a sample of 108 mothers and 108 schoolchildren. Mothers answered a previously validated survey to evaluate their healthy eating and nutrition knowledge level. The schoolchildren’s nutritional status was determined by the body mass index. The Chi-square test and Fisher’s exact test at significance level α=0.05 was used with the STATA 14.0 program. Results: Overnutrition was found in 67.8% of the schoolchildren, which was not related to mealtimes (p=0.52), income level (p>0.05), healthy eating knowledge (p=0.87), and mothers’ nutrition (p=0.33). The relationship between nutritional status and gender (p<0.05) and the mothers’ perception of their children’s NS (p<0.0001) was determined. Conclusion: The schoolchildren’s nutritional status was not statistically related to their mothers’ healthy eating and nutrition knowledge level even when the knowledge level was insufficient.