Diet during adolescence can have lasting effects on nutritional status, health, and development. We hypothesized that dietary patterns with low-quality nutrition are associated with overweightness. We collected data for 882 Chilean adolescents from the Growth and Obesity Cohort Study (mean age: 12 years). Dietary intake was assessed through 24-h recalls and weight status data were obtained during clinical visits. Dietary patterns were obtained through exploratory factor analysis. Multiple logistic regression models were used to examine cross-sectional associations between dietary patterns and overweight (BMI z-score ≥ 1SD). Four dietary patterns were identified: “Breakfast/Light dinner”, “Natural foods”, “Western”, and “Snacking”. “Breakfast/Light dinner”, “Western”, and “Snacking” patterns provided higher energy and excess nutrients (sodium, saturated fat, and added sugar). Moreover, adolescents with higher adherence to “Western” or “ Snacking” patterns (third tertile) had higher odds of being classified as overweight (OR = 1.67; 95%CI: 1.103–2.522 and OR = 1.86; 95%CI: 1.235–2.792, respectively) than those with lower adherence (first tertile). “Natural foods” pattern was also associated with overweightness (OR = 1.83; 95%CI: 1.219–2.754). These dietary patterns were associated with overconsumption of nutrients of public health concern. Three of the four main dietary patterns were associated with overweightness. These results highlight the need of prioritizing adolescents on obesity prevention strategies.