The study objectives were to gain insight into how the terms 'dieting' and 'binge eating' are understood and used by adolescents and to assess whether interpretations of these terms are consistent across age and gender. Twenty-five focus groups were conducted with 203 adolescents (138 girls and 65 boys) in urban public junior and senior high schools. Respondents were asked questions about dieting and binge eating behaviors. In the majority of groups (n=19), healthful eating behaviors, such as eating less fat or more fruits and vegetables, were mentioned in reference to dieting. However, in many of the groups (n=13) unhealthful eating behaviors, such as skipping meals or 'starvation,' were also described. Dieting was frequently described as an umbrella term for different behaviors aimed at weight control (ie, physical activity) or in nonbehavioral terms (ie, as a desire or plan for weight loss). Although binge eating was described as overeating by many participants, often it was not clear if youth were referring to uncontrolled overeating. In nearly half of the groups, participants indicated unfamiliarity with the term 'binge eating.' There was some confusion between binge eating and other forms of disordered eating. The findings suggest that prevalence rates of self-reported dieting and binge eating behaviors should be interpreted with caution and it should not be assumed that the majority of adolescents who self-report dieting are engaging in unhealthful behaviors. In providing nutrition counseling to youth, and in assessing dieting and binge eating behaviors in clinical settings and in research studies, specific behaviors should be defined.