Objective: Existing reviews provided evidence for the associations between higher physical activity (PA) and lower negative symptoms of psychosis among people with schizophrenia. This meta-analysis goes beyond existing syntheses and investigates associations between PA, positive and negative symptoms of psychosis, as well as symptoms of general psychopathology (referring mostly to cognitive functioning) among people with schizophrenia, but also other psychotic disorders. The moderating roles of the type of diagnosis and the type of exercise intervention were explored. Methods: The study was registered with PROSPERO (CRD42018118236). Six electronic databases were searched; n = 27 experimental and observational studies were included, and psychotic symptoms-related data were recorded in one direction (higher values indicate better mental health and lower symptomatology). Results: Higher levels of PA (or participating in PA interventions) were associated with better mental health, that is, lower levels of positive symptoms (all studies: r = 0.170; experimental studies: SMD = 0.677), negative symptoms (all studies: r = 0.214; experimental studies: SMD = 0.838), and general psychopathology (all studies: r = 0.451; experimental studies: SMD = 1.511). The type of diagnosis (schizophrenia vs. other psychotic disorders) did not moderate these associations. Conclusions: We found a consistent pattern of associations between higher levels of PA and lower positive, negative, and general psychopathology symptoms in people with schizophrenia and those with other psychotic disorders.