Objective To explore 5-year-old girls' ideas, concepts, and beliefs about dieting. Design Girls were asked to define dieting, to describe the behaviors dieting comprised, and were queried about links between dieting, weight control, and body shape. Parents completed questionnaires addressing family health history, demographics, and issues related to food, dieting, and weight control. Subjects/setting Participants were 197 girls aged 5 years and their parents. All girls lived with both biological parents, and were without food allergies or chronic medical problems. Statistical analyses performed For 5 open-ended questions related to dieting, girls were categorized as either having or not having ideas about dieting. These ideas, concepts, and beliefs were categorized, and logistic regression examined predictors of girls' ideas about dieting. Results Depending on the question, from 34% to 65% of girls aged 5 years had ideas about dieting. Compared to girls whose mothers did not diet, girls whose mothers reported current or recent dieting were more than twice as likely to have ideas about dieting, suggesting that mothers' dieting behavior is a source of young girls' ideas, concepts, and beliefs about dieting. Among mothers, more than 90% reported recent dieting, and most reported use of both health-promoting and health-compromising dieting behaviors. Applications Women should be informed that weight control attempts may influence their young daughters' emerging ideas, concepts, and beliefs about dieting. Mothers should be encouraged to use health-promoting rather than health-compromising weight control strategies, not only for their own well being, but to reduce the likelihood that daughters will incorporate health-compromising dieting behaviors into their concepts, ideas, and beliefs about dieting.