(1) Background: Nutrient-poor, energy-dense food and beverage (F&B) advertisements influence children’s food preferences, consumption, and purchase requests, contributing to overweight and obesity. Objective: To characterize the nutritional quality of F&B advertised by product placement (PP) in Mexican television programs with the highest audience ratings for children. (2) Methods: A total of 48 h of television programs between December 2016 and January 2017 during the hours with the highest ratings for children were analyzed. Nutritional quality was assessed through the Mexican Ministry of Health (MMH-NPM), the World Health Organization Regional Office for Europe (WHO-Europe), and the Pan American Health Organization nutrient profile models (PAHO-NPM). (3) Results: A total of 119 F&B were broadcast, of which more than 60% were unhealthy according to the three nutritional models. Reality shows and movies presented the most PP advertising. The food category most frequently advertised was sugar-sweetened beverages (41.2%). F&B advertised in children’s programs had a higher content of energy, total fat, and saturated fat ( < 0.01). (4) Conclusion: The MMH-NPM was the most permissive and the PAHO-NPM was the strictest for evaluating nutritional quality. Mexico must strengthen the regulation of advertising to protect children from its negative effects on health.