<p>Although teachers are particularly vulnerable to work-related stress, their mental health has received limited scholarly attention. This study investigated the one-year trajectories of depressive and anxiety symptoms among Chinese school teachers and examined how these patterns varied by individual characteristics. A three-wave longitudinal survey was conducted between April 2021 and June 2022, involving 3,634 teachers from Shenzhen, Guangdong Province (mean age at baseline = 34.69 years). Growth Mixture Modeling and multinomial logistic regression were employed to identify developmental trajectories and their predictors, respectively. Three distinct trajectories emerged for both depressive symptoms (dysfunction: 4.8%; mild: 48.7%; resistance: 46.5%) and anxiety symptoms (dysfunction: 6.0%; mild: 40.2%; resistance: 53.8%). Teachers who were older, married, or taught physical education were less likely to experience persistent or mild psychological symptoms. In comparison, employment in public schools, lack of exercise, sleep disturbance, chronic physical illnesses, and exposure to negative life events were associated with a higher likelihood of being in the mild symptom group. Teachers who lacked exercise, experienced sleep disturbance, suffered from chronic physical illnesses, had a family history of psychiatric disorders, or encountered negative life events were more likely to follow a dysfunctional trajectory. These findings highlight the heterogeneous mental health trajectories among Chinese teachers and emphasize the need for tailored preventive and therapeutic strategies for those at higher risk.</p>