In Mexico, about one third of school-age population is overweight or obese and the diet is one of the main determinants. The purpose of this study was to identify the dietary patterns of Mexican school-age children and to determine their association with the risk of overweight/obesity. This study included 8252 school-age children who participated in the 2006 National Health and Nutrition Survey (ENSANUT-2006). Dietary data were collected using a 7-day Food Frequency Questionnaire (FFQ). Foods were classified into 25 groups and dietary patterns were defined by cluster analysis. Body Mass Index and prevalence of overweight/obesity were calculated. Logistic regression models were used to evaluate the association between dietary patterns and overweight/obesity. Five dietary patterns were identified: Rural dietary pattern (high intake of tortilla and legumes), sweet cereal and corn dishes pattern (high intake of sugary cereals, tortilla, and maize products); diverse pattern (intake of several food groups); western pattern (high intake of sweetened beverages, fried snacks, industrial snack cakes, and sugary cereals), and whole milk and sweet pattern (high intake of whole milk and sweets). We found that children with sweet cereal and corn dishes and western dietary patterns showed an association with overweight and obesity (prevalence ratio 1.29 and 1.35, respectively, using as reference the rural dietary pattern). Patterns characterized by high intakes of sugary cereals, sweetened beverages, industrial snack, cakes, whole milk, and sweets were associated with a higher risk of overweight/obesity among in Mexican school-age children.