Background While the relationship between negative aspects of body image and positive schizophrenia symptoms was extensively investigated and is relatively well-established, there is a dearth of literature on the relationship between positive symptoms and positive aspects of body image, such as body appreciation and functionality appreciation, in patients with schizophrenia. This study aimed to (1) compare weight stigma, body and functionality appreciation between obese/overweight and normal-weight patients with schizophrenia, and (2) explore the associations between these variables and positive psychotic symptoms in the obese/overweight group. Method A cross-sectional study was conducted in the Psychiatric Hospital of the Cross, Lebanon during September 2022 recruiting selected in-patients diagnosed with schizophrenia. Patients were classified as overweight/obese if they had a BMI > 25 (N = 76 (37.25%), aged 55.57 ± 11.30 years, 42.6% females). The Weight self‑stigma questionnaire, the Functionality Appreciation Scale, and the Body Appreciation Scale, and the Positive and Negative Syndrome Scale (PANSS) were used. Results No significant difference was found between overweight/obese and normal-weight patients for all variables, except for weight stigma; a significantly higher weight stigma score was significantly found in overweight/obese compared to normal-weight patient. In the bivariate analysis, higher functionality appreciation was significantly associated with higher positive PANSS scores. The results of the linear regression, taking the positive PANSS score as the dependent variable, showed that higher functionality appreciation (Beta = − 0.52) and higher social support (Beta = − 0.16) were significantly associated with lower positive PANSS scores, whereas having a secondary education level compared to illiteracy (Beta = 7.00) was significantly associated with higher positive PANSS scores. Conclusion Although based on cross-sectional data, these findings preliminarily suggest that higher functionality appreciation can help reduce the severity of positive psychotic symptoms in overweight/obese schizophrenia patients, and that interventions aimed at improving functionality appreciation could be regarded beneficial therapeutic targets in the treatment of psychosis.