Objective: Assessment of the level of social functioning is important especially for people with schizophrenia that has a chronic course of illness. The purpose of this study was to develop a culturally sensitive, user-friendly scale that could assess the social functioning of the people with schizophrenia living in Turkey. Methods: After examining the studies that assessed social functioning in people with mental illnesses and social habits of people living in the community, a 28-item scale was formed. The items of the form were discussed with patients with schizophrenia and their family members. Items, which were difficult to comprehend, were reevaluated and the form was finalized as Social Functioning Assessment Scale (SFAS). One hundred and forty-eight outpatients with schizophrenia or schizoaffective disorder were given the SFAS, Positive and Negative Symptoms Scale (PANSS), Clinical Global Impression-Severity (CGI-S), and Global Assessment of Functioning (GAF). At the same time, Social Functioning Scale (SFS) and SFAS were filled out by the relatives of the patients living together. SFAS was also given to 161 healthy subjects living in the community. For reliability analyses; internal consistency coefficient, item-total correlation, and test-retest reliability were assessed. For validity analyses; explanatory factor analysis, convergent, divergent, and discriminant validity were examined. Results: The data from 120 patients with schizophrenia and 28 with schizoaffective disorder was examined. Cronbach's alpha coefficient for SFAS total score was 0.842. Kaiser-Meyer-Olkin value was 0.813, and Bartlett test was significant for factor analysis. In explanatory factor analysis, SFAS comprised of three factors (interpersonal relations and recreation, self-care, independent living) and they can explain 47% of the total variance. Occupational life could not get in any of the factors; however, since it was important for social functioning, it was added to the scale as the fourth factor. Total score of the SFAS filled out by the patients was significantly correlated with PANSS, CGI-S, GAF and SFS total score. There was a satisfactory correlation between the total score of SFAS filled out by the patients and relatives. There was a statistically significant difference between the SFAS scores of the patients and SFAS scores of the controls. Test-retest reliability of the SFAS-P was 0.874. Conclusion: Regarding the findings of the study, SFAS was considered a culturally sensitive, easy-to-use, valid and reliable instrument that objectively assesses the social functioning of the patients with schizophrenia.