Background: People living with mental illness are facing many problems regarding their illness and stigma which consequently affect their self-concept. Aim: This study aimed to assess the stigma and its relation to self-concept among patients with mental disorders. Design: A descriptive correlational research design was utilized in this study. Setting: This study was carried out in the outpatient clinic of the mental health hospital, affiliated to AlFayoum University Hospitals... Subjects: This study was conducted on 246 patients with mental disorders. Sample type: Purposive sample was recruited for this study. Data collection tools: Data were obtained through three tools; 1) Interviewing Questionnaire to assess socio-demographic data and medical history of the patients with mental illness, 2) The internalized stigma of mental illness inventory, and 3) Self–concept Questionnaire. Results: this study revealed that, nearly three quarter of the studied sample (74.8%) experienced stigma, 46.3% of them had fair self-concept and more than third of them 36.6 had low self-concept, however there were statistical significance relation between stigma and levels of self– concept and the most affected domain was self-criticism. Conclusion: this study results concluded that, the majority of the studied sample experienced stigma, and less than half of them had fair self- concept, more than third of them had low self-concept, and there were statistical significance relation between stigma and total levels of self–concept. Recommendations: There is an urgent need for developing and implementing strategies to fight stigma associated with mental disorders which consequently affect their self-concept.