This study aims to examine the level of knowledge, attitude and practices (KAP) of adolescents towards sugar-sweetened beverages (SSB), together with the associated factors that determine their KAP. Data were collected using self-administered questionnaires that consisted of sociodemographic, the KAP for the SSB questionnaire, and the Beverage Intake Questionnaire (BEVQ). The respondents' heights, weights, waist circumferences and body fat percentages were measured. This study involved 439 adolescents aged between 13 and 17 years old, in public secondary schools in Selangor, Malaysia. The results reveal that 35% of the adolescents were overweight, 26% had a high waist circumference, and 45% had a high body fat percentage. Caffeinated drinks and full cream milk were the most frequently consumed SSBs. The KAP score revealed a good attitude (88.4%), a moderate knowledge (51.8%) and a poor practice (40.5%). Those with a higher body fat percentage showed significantly good attitude scores (p < 0.05). Low household income groups, females, adolescents aged 16-17 years old and being from an urban area demonstrated a significant (p < 0.05) positive determinant towards the KAP score. In conclusion, high awareness of negative health outcomes associated with SSBs among adolescents was not in accordance with the level of their lifestyle choices.