Psychotic-like experiences (PLEs) may be important antecedents of psychosis and other mental disorders.To investigate distinct longitudinal trajectories of the frequency of PLEs and their relationship to subsequent development of mental disorders.A longitudinal study of self-reported PLEs and concurrent traumatic experiences was conducted among 6,198 adolescents through annual classroom assessments over 3 years (2014-2016) using the Community Assessment of Psychic Experiences and the Trauma History Questionnaire. Diagnoses of mental disorders were based on the Mini-International Neuropsychiatric Interview in the final year. Growth mixture modeling was used to identify distinct growth trajectories in the frequency of PLEs. Logistic regression was then used to explore relationships between different PLE trajectories and emergence of psychiatric disorders, taking account of sociodemographic characteristics and childhood antecedents.Two different PLE trajectories were identified, one characterized by stable low levels of PLE frequency and the other by progressively increasing PLE frequency. Transition to mental disorder occurred in 3.39% of the increasing-frequency group and 1.28% of the stable low-level group. The increasing-frequency group had a significantly higher risk of transition to any psychiatric disorder (OR = 2.7; 95% CI, 1.56-4.66), to a psychotic disorder (OR = 22.14; 95% CI, 2.30-213.25), and to a nonpsychotic psychiatric disorder (OR = 2.28; 95% CI, 1.27-4.10). Besides increasing PLEs (OR = 3.33; 95% CI, 1.55-7.19), other risk factors for any psychiatric disorder included childhood trauma (OR = 1.17; 95% CI, 1.01-1.36), family divorce (OR = 2.86; 95% CI, 1.24-6.61), and minority ethnicity (OR = 2.91; 95% CI, 1.18-7.20).The pattern of increasing PLEs predominates in predicting emergent mental disorder, particularly psychosis, along with minority status, trauma, and family divorce, suggesting potential targets for preventive intervention.