Purpose: This study was conducted to explore psychological flexibility’s mediating effect on the relationship between symptoms, social functioning and quality of life among inpatients with schizophrenia. Methods: Participants were 190 inpatients with schizophrenia from five mental hospitals in three areas. Data were collected from self-report questionnaires administered from June to July 2018. Data were analyzed using Pearson’s correlation coefficients and the Baron and Kenny method with IBM SPSS 22.0. Results: Quality of life showed a positive correlation with psychological flexibility (r=.52, p<.001), but a negative correlation with symptoms (r=-.39, p<.001) and social functioning (r=-.42, p<.001). Psychological flexibility had a full mediating effect on the relationship between symptoms and quality of life. Psychological flexibility also showed partial mediating effects on social functioning and quality of life. Conclusion: The results suggest that psychological flexibility plays an important role in the quality of life of inpatients with schizophrenia. Therefore, mental health practitioners should focus on interventions to improve their social functioning and psychological flexibility to improve their quality of life.