Purpose: The current study provides a comprehensive analysis of the content of advertisements on Web sites targeted at adolescents, with a particular focus on the female beauty ideal. Methods: Advertisements (N = 631) from 14 Web sites popular with adolescents were analyzed with respect to product advertised, characteristics of people presented, and emphasis on appearance and the thin beauty ideal. Results: Although a wide variety of products were featured, advertisements for cosmetics and beauty products were the most frequent. Further, many of the products advertised (e.g., dating services, weight loss products, gambling games) might be considered inappropriate for the intended audience (i.e., teenagers) of the Web site. People who were a part of advertisements were generally female, young, thin, and attractive. Advertisements for games, weight loss products, and cosmetic and beauty products strongly focused on appearance and laid emphasis on the thin ideal. Conclusions: Like advertisements in mainstream media, advertising on the Internet perpetuates the stereotypical ideal of feminine beauty. Adolescents using the Internet are likely to be exposed to numerous advertisements that reinforce the importance of beauty and thinness, which could have a detrimental impact on how they feel about their bodies.