The adolescent developmental stage has been described by researchers as a period in which decision-making abilities and independence skills are developed; therefore, this period may attract more attention from health-care providers as a key time for establishing healthy life styles and positive adaptive behaviours, such as nutritional behaviours. Methods: A quasi-experimental control group, and post-test only design was used. A school-based healthy nutrition educational programme was implemented to improve the nutritional knowledge of adolescents, and to promote a healthy life style among them. The 'Let's Eat Healthy' programme was delivered to 150 students in the intervention group, who were compared to another 150 students in the control group where the programme was not delivered. Results: Students that participated in the intervention group were significantly more knowledgeable about healthy nutrition compared to students that didn’t participate (P<0.01). They also scored significantly higher in the dietary behaviours survey, which reflects the adoption of more healthy eating behaviours. Conclusions: The results of the study revealed that such a programme would be effective in promoting more nutritionally healthy life styles, thus preventing obesity and nutrition-related disease among adolescents in United Arab Emirates (UAE) schools.