Little information exists about health-risk behaviors in Jordanian adolescents especially among 15 - 19 years olds. The purpose of this study was to assess the patterns of three of health-risk behaviors, namely, diet, physical activity, and tobacco use of the Jordanian adolescent students aged 15 to 19 years old, and to compare the patterns of these behaviors between male and female adolescents. A descriptive cross-sectional design was used. A multi-stage stratified random sample was obtained from the public school educational directorate, which is affiliated to Amman governorate. A random sub sample of eight public comprehensive secondary schools was selected, four schools for females and four schools for males. A total of 750 students (375 boys and 375 girls), their ages between 15 - 19 years were included in the analysis. Data were collected by using two tools: students’ profile structured questionnaire (tool 1), and a modified version of the General School Health Survey questionnaire (tool 2). The findings of this study showed that 10.7% of students were overweight and 4.9% were obese. The majority of students had eaten less than the daily requirements of fruits, vegetables, and milk daily, while the intake of soft drinks was higher than recommended. One-fifth of students had been physically active at least 60 minutes daily. Overall, (55.5%) had tried smoking and 44.0% had smoked any other form of tobacco such as water pipe. Moreover, 62.4% had tried to quit smoking cigarettes. Furthermore, there were significant differences between males and females regarding these risk behaviors. In conclusion, there are problems with Jordanian adolescents relating to diet, physical activity, and tobacco use. The results highlight the need for effective school health program that combines education, counseling and behavioral skill building along with environmental support to enhance students’ efforts, intentions, and strategies to overcome these risk behaviors. In addition, the findings could help policy makers to strength strategies and policies to maintain healthy adolescents and schools