Background: The purpose of the study was to assess adolescents' perceptions of controllability and its relation to weight stereotypes as a function of gender. Methods: Two hundred and thirty-one seventh and eighth graders from physical education classes completed a perception of controllability questionnaire and weight stereotype explicit scale ratings. Results: Analysis of variance and chi-square analyses indicated that adolescents had high perceptions of controllability, namely the perception that one can control one's weight with diet and exercise. Perceptions of controllability were weakly associated with the endorsement of stereotypes toward the overweight. Results from chi-square analysis on individual statements related to causality of obesity indicated that participants may not have a complete understanding or be receiving appropriate messages about the etiology of obesity. Also, 2-way chi-square analyses indicated that boys more frequently believed in personal control than girls, and girls indicated more frequently that they were unsure whether obesity was children's fault. Conclusion: Teachers need to be cognizant of the messages that are relayed to students about the etiology of obesity if they are looking to positively impact students' healthy lifestyle behaviors and personal and social responsibility. Also, populations (eg, gender) may need to be considered when delivering these messages. (Contains 3 tables.)