Although much is known about health-risk behaviors of adolescents, less is known about their health-promoting behaviors. The purpose of this analysis was to compare health-promoting behaviors in adolescents in Grades 9-12 by gender and ethnicity and explore how these behaviors changed over time. Data were collected from 878 rural adolescents (47.5% Hispanic; mean age at baseline 14.7 years). Males from all ethnic groups scored significantly higher than all females on physical activity; non-Hispanic Black males and females scored significantly higher than other ethnic groups on safety behaviors. Hispanic and non-Hispanic White females scored higher than males in these ethnic groups on stress management. Nutrition, physical activity, and safety behaviors decreased significantly for most participants from Grade 9 to 12 whereas stress management remained relatively stable. Findings are similar to those from nationally representative samples that analyzed cross-sectional data and have implications for school nursing interventions to improve health-promoting behaviors in rural adolescents.