This study aims to determine the effect of physical activity on cognitive restraint, uncontrolled eating and emotional eating in individuals with a psychotic disorder. Twenty-seven participants with a psychotic disorder (55% male; mean age: 30 ± 7.5 years; Caucasian: 66.7%; schizophrenia spectrum disorders: 44.4%; bipolar disorder with psychotic features: 29.6%) took part in a 6-month bi-weekly physical activity program (walking, running, yoga, cycling and dancing). The Three-Factor Eating Questionnaire was used to assess participant's eating behaviours, and the frequency of completed physical activity sessions was compiled. The mixed models analysis approach revealed that the level of cognitive restraint remained unchanged (pre: 39.2 ± 18.7 vs. post: 44.1 ± 18.3; p = 0.24), while the levels of uncontrolled eating (pre: 39.7 ± 19 vs. post: 31.6 ± 19.7; p = 0.02) and emotional eating (pre: 45.5 ± 22.3 vs. post: 32.2 ± 22.2; p < 0.001) decreased at the end of the 6-month physical activity program. This study showed that physical activity has positive effects on disordered eating behaviours in individuals with a psychotic disorder, similarly to previous studies on other populations (e.g., overweight and obese participants, postmenopausal women). Further studies are warranted to better understand the role of physical activity in moderating eating behaviours.