Objective: This study was conducted to evaluate the beliefs and attitudes of nurses/physicians, patients and patients' relatives towards stigma in psychiatry clinics. Method: The study was undertaken using descriptive-sectional study method. It was conducted between October-December 2017 at the psychiatry clinic of two state university training and research hospitals and at the mental health and diseases training and research hospital of a state university. The sample consists of 43 nurses/physicians, 76 patients and 37 patient relatives. The data were collected using Beliefs towards Mental Illness Scale (BMI), scale of The Community Attitudes towards the Mentally Ill (CAMI) and Internalized Stigma of Mental Illness Scale (ISMI). The beliefs and attitudes scores of nurses/physicians, patients, and patient relatives were compared, the internalized stigmatization levels of patients with mental disorders were evaluated, and the stigma belief and attitude levels were examined for some variables. Results: Participants in the study were 27.6% nurses/physicians, 48.7% patients and 23.7% patient relatives. A statistically significant difference was found between the groups in terms of the BMI subscales of dangerousness, poor social and interpersonal skills and incurability and shame, and the scale total score (p < 0.05). A statistically significant difference was found between the groups in terms of CAMI fear/exclusion score (p < 0.05). Discussion: It was determined that patients have the most negative beliefs towards to mental disorders/patients, also nurses/physicians were found to exhibit more fear and exclusion attitudes. Although it varies according to the groups it was determined that beliefs, attitudes and internalized stigmatization were affected by variables such as economic status, education level, gender, and number of hospitalizations.