Objective: To examine the trajectory of anger and its psychosocial predictors (i.e., perceived social inequality, relative deprivation, and loneliness) as well as its association with anxiety and depression. Participants/Method: Students (N = 365) completed an online survey three times over a one-year period. Results: Three trajectories of anger were identified by growth mixture modeling: "low/stable" (i.e., a low and stable anger over time; 88.0%), "low/increasing" (i.e., a low level of anger with an increasing trend; 6.7%), and "moderate/decreasing" class (i.e., a moderate level of anger with a decreasing trend; 5.3%). A greater perception of relative deprivation, but not of perceived social inequality, was associated with the "low/increasing" class. A greater level of loneliness was associated with the "moderate/decreasing" class. Symptoms of depression and anxiety were higher in the "moderate/decreasing' and "low/increasing" class than in the "low/stable" class. Conclusions: These results suggest that interventions targeted at anger may benefit from addressing perceptions of relative deprivation and loneliness.