Background: Despite the growing realization regarding the importance of adverse childhood experiences (ACEs) in adult health outcomes, this area of research has received little scientific attention in low- and middle-income countries, including India. Aims: To understand the overall and domain-specific association of exposure to ACEs with current depression, anxiety, stress, and well-being among young adults of Delhi-NCR. Methods: This cross-sectional study was carried out among 1,812 young adults (aged 18–25 years) of both sexes (68.7% females). Fieldwork was conducted on the campuses of the University of Delhi, Delhi, and Amity University, Noida, India. ACEs, depression, anxiety, stress, and well-being were screened using the Adverse Childhood Experiences International Questionnaire, Beck Depression Inventory-II, Beck Anxiety Inventory, Perceived Stress Scale, and WHO-5 Well-Being Index, respectively. Results: Exposure to ACEs was found to increase the odds of moderate/severe depression, moderate/severe anxiety, and high stress and decreased the odds of good well-being in a dose-response manner. Being bullied, followed by emotional abuse, was associated with the highest odds of current moderate/severe depression, moderate/severe anxiety, and high stress and the lowest odds of good well-being. Further, while several domains of household dysfunction showed poor association with studied mental health outcomes, domains of abuse and violence were more consistently associated. Conclusions: The present study revealed the detrimental impact of ACEs on mental health outcomes among young adults of Delhi-NCR, India, and underscored the relevance of ACEs in the Indian context. Considering the lack of trauma awareness in Indian societies, there is an urgent need to create widespread awareness regarding ACEs and associated health implications.