Children are massively exposed to food marketing through television and other forms of media. Marketing strategies promote unhealthy eating behaviours and contribute to childhood obesity. The main aim of this study was to assess the potential exposure and power of food advertisements aimed at children, broadcasted on Portuguese television. Television data was recorded for two weekdays and two weekend days between 6 am and 10 pm during November 2021 from four free-access Portuguese television channels. Data was analysed according to the World Health Organization television protocol and Portuguese Legislation. We identified 5272 advertisements, of which 11.2% were for food and beverages (n = 590). Most advertised food categories for children and adolescents were chocolate and bakery products (42.0%), soft drinks (26.7%), and yoghurt (16.0%), and none met the nutritional profile outlined by the national legislation. Unhealthier food advertisements targeting youth were shown in children's non-peak time and morning during news and entertainment programmes. Product uniqueness, humour, and fun were the most frequent primary persuasive techniques. Most advertisements showed a high use of brand logos, product images, and premium offers. In conclusion, Portuguese children and adolescents are potentially exposed to large numbers of unhealthy food advertisements on television, despite marketing regulation and restriction policies.