The study found that both bullying and sexual harassment had a significant negative impact on girls' health. The frequency of both bullying and sexual harassment increased from middle school to high school, which might be due in part to the small number of girls in the high-school sample. The study suggests, however, that high-school girls are less vulnerable to the negative impacts of bullying and sexual harassment than middle-school girls. This suggests that older girls are better able to insulate themselves from the potentially adverse health effects of bullying and sexual harassment. They may have developed coping strategies and peer support groups that enable them to deal with bullying and sexual harassment. Regardless of grade level, the findings indicate that lesbians experienced more bullying and sexual harassment than other girls, and they scored lower on several health measures. Few differences were related to race or disability. The vulnerability of middle-school girls to both bullying and sexual harassment suggests the need for programs and training that target these problems earlier than is currently the case. Data were obtained from 369 middle-school and 199 high-school students from 4 suburban New England schools (2 middle schools and 2 high schools). The girls completed paper-and-pencil surveys. Questions addressed a range of topics that included student experiences with sexual harassment and bullying, health and well-being, and attitudes toward school and teachers. 5 tables and 34 references