Academic-related demands that exceed students’ adaptive capabilities are collectively known as academic stress. High levels of academic stress are associated with an increased likelihood of depression, insomnia, substance addiction, self-harm, suicidal ideation, and subsequently, quitting education. Globally, academic stress is now a common phenomenon due to COVID-19-induced changes in the education system. Knowledge of the magnitude of academic stress and its factors can enable early recognition, intervention, and alleviation of the problem. The objective of this study was to assess the magnitude of perceived academic stress and identify the main stressors through a cross-sectional survey using the Manipal Inventory of Academic Stress scale. The study participants involved 2152 Grade 11 and 12 Commerce students enrolled in 34 pre-university colleges in coastal Karnataka. A stratified cluster sampling method was used in the study. Statistical methods, namely descriptive statistics, multiple linear regression analysis, two-sample independent t-test, and one-way ANOVA tests, were used in the study. The study observed that one in every four pre-university students experienced high levels of perceived academic stress. Parent expectations, academic queries from neighbours and relatives, and lack of time for revision were identified as the top three stressors. Gender, grade, and mother’s education were associated with academic stress. Interventions at the individual, family, institutional, and community levels are the need of the hour to safeguard adolescents from negative experiences that might deprive them of wellness in their future.