Background: University students report high levels of adverse childhood experiences (ACEs), which can lead to severe mental health problems. Understanding how ACEs impact well-being in this population is essential, yet research to date is limited. Objective: To explore ACE patterns and their association with lower well-being in university students. Participants and setting: 1023 Spanish students (71.6 % female) aged between 18 and 64 years old (M = 20.10, SD = 3.93) completed a self -report questionnaire. Methods: This study used a cross-sectional design. The ACE International Questionnaire (ACE -IQ) and the Short Warwick -Edinburgh Mental Well-being Scale were used to assess, respectively, childhood adversities and mental well-being. Latent Class Analysis and regression modeling were conducted to analyze the link between ACEs and lower mental well-being, considering the covariates of age, country of origin, sexual orientation, and mental illness. Results: Four ACE classes were identified: Low ACEs (49.5 %), Dysfunctional Household (12.3 %), Household and Peer Abuse (31.0 %), and High ACEs (7.2 %). The regression analysis ( F (3, 1007) = 19.2, p < .001, R-adj(2) = 0.054) successfully predicted well-being scores based on ACE classes. When compared with the Low ACE class, all other classes exhibited lower levels of well-being. Age, sexual orientation, and mental illness were also related to lower well-being, with mental illness having the strongest negative effect ( beta = -0.635, t (1015) = -6.49, p < .001). Conclusions: These findings underscore the relationship between childhood adversity and mental health, offering insights for future prevention efforts and enriching our understanding of ACEs and their impact on well-being.