Background: Essential hypertension is one of the fastest rising noncommunicable diseases among adolescents and poses a major public health issue globally. This study aimed to estimate the prevalence of prehypertension and hypertension among school-going adolescents in Chennai and also to delineate the role of nutritional and environmental determinants in the development of hypertension. Methods: This cross-sectional study was conducted among school-going adolescents aged 14 to 18 years in northern Chennai. Four schools (two private, two public) out of 21 were selected randomly using probability proportionate to sampling size and 401 students were recruited after consent. Data were collected using an adapted modified World Health Organization (WHO) Global School-based student Health Survey (GSHS) questionnaire; anthropometry and blood pressure measurements were done by trained healthcare professionals using standard procedures. Prehypertension was defined when systolic or diastolic pressure >90th percentile and <95th percentile; hypertension when systolic or diastolic pressure >95th percentile. Data were analyzed using SPSS, descriptive statistics like frequencies, mean, and percentages were used and inferential statistics like Chi-square test and logistic regression were used to elicit predictors of essential hypertension. Results: Out of 401 participants, 185 (46.1%) were males and 216 (53.9%) were females. Overall prevalence of prehypertension and hypertension was 14.2% and 5.5%, respectively. Gender (P = 0.039), overweight/obese (P = 0.000), junk food intake for >3 days/week (P = 0.000), physical inactivity for <3 days/week (P = 0.000), and parent's history (P = 0.005) were significant determinants in the development of prehypertension and hypertension. Conclusions: Nutritional and environmental determinants play a critical role in influencing blood pressure status among adolescents, this requires lifestyle and behavioral modification.