ObjectivesTo determine the extent, common types and the impacts of negative peer pressure and bullying among adolescents within the school environment. MethodologyA cross sectional study was carried out including Sinhalese adolescents in grades 9, 10 and 11 in the district of Kandy. Twelve schools were selected randomly to represent each category of schools namely 1AB, 1C and 2 and a class was considered as a cluster. Details on events and experiences as victims of negative peer pressure and bullying were collected using a self-administered questionnaire. ResultsThe sample consisted of 896 students with a mean age of 15 years (SD= 0.86).Fifty two percent (n= 466) were boys. Peer pressure on substance use and of financial type was significantly more for boys. Peer pressure for sexual activities was reported by 14.6% of boys and 11.2% of girls. A significantly higher proportion of boys (78.1%), were victims of physical bullying than girls (26.5%) (p<0.001). More girls were victims of verbal bullying (82.1%) than boys (50%) (p<0.001).Of the sample, 53.3% were victims of relational bullying. Of the boys, 16.7%, 12.2% and 10.3% were compelled to smoke, use alcohol or use illegal abusive substances. Drop in school performance, staying away from school and extra-curricular activities, engaging in homo-sexual and hetero-sexual acts, feeling of hatred and suicidal thoughts were some of the undesirable impacts reported. ConclusionHigh prevalence and the harmful effects of negative peer pressure and bullying observed provide compelling reasons to initiate interventions.