Background: Youth obesity in the United States is a major health concern. Obesity can be reduced by increasing health-promoting behaviors. Purpose: The goals of the present study were to (1) identify the strongest motivators of and barriers to health-promoting behaviors among a culturally diverse group of middle and high school students and (2) determine whether these motivators and barriers differed by age, gender, race, and grade classification. Methods: Subjects were 591 sixth- through 12th-grade students enrolled in a public school. Results: A strong motivator for engaging in health-promoting behaviors is awareness of the health benefits of engaging in these behaviors. Strong barriers to engaging in health-promoting behaviors are preferences for unhealthy drinks and temptation to eat unhealthy foods. Additionally, there are significant differences in association with race/ethnicity and grade classification. Discussion: This study is unique in that youth rather than professional experts were asked to rate the strength of the motivators of and barriers to health-promoting behaviors. Translation to Health Education Practice: The results of this study have important implications for promoting healthy eating and drinking among middle school and high school students.