Stigma may play a role in medication adherence by its influence on client’s behavior in term of seeking treatment. The present study aims to identify the association between internal stigma and medication adherence, the influence of mental illness stigma on medication adherence, and the associations among patients’ socio-demographic characteristics, mediation’s adherence, and stigma. A descriptive, analytical study was established with a purposive sample of (60) patients with schizophrenia who are attending outpatient clinics at a psychiatric teaching hospital in baghdad. The study instrument was adopted and modified by the researcher. A self-administered report was used as a means for the purpose of data collection. The descriptive and inferential statistical approaches were used for the purpose of data analyses. The results showed that the level of the Medication Adherence Scale was moderate among most of the scale items. The Internalized Stigma Scale indicated a moderate level of mental illness stigma among patients (63.3%). The finding also indicated that mental illness stigma has no significant influence on medication’s adherence. The findings revealed that there is high significant association between medication’s adherence and age groups of patients. There is high significant association between mental illness stigma and patients occupation. The study concluded that mental illness stigma has no influence on medication adherence among patients with schizophrenia.