As future pharmacists, pharmacy students have the chance to obtain necessary information about mental illnesses in their faculty education and internships. Their gained observations, experiences, awareness, and knowledge throughout their degree will affect their beliefs, attitudes, and future behaviors toward mentally ill patients. In this regard, the study aims to determine pharmacy students' actions towards mentally ill patients by evaluating its antecedents, such as beliefs and attitudes. A survey was applied to pharmacy students in Ankara, Turkey. Exploratory factor analysis was used to determine the factor structure, and confirmatory factor analysis was used to verify them. Then, the comprehensive structural equation model was proposed to explain the relations of them to each other. Behavior toward mentally ill patients (BMIP) model was proposed. According to the BMIP model, students' beliefs about how mentally patients are dangerous, and how mental illness is incurable are posited to be positively related to negative attitudes towards those with mental illness, which in turn influence behaviors towards them. The BMIP model can be a guide not only for pharmacy students' behaviors in their professional life but also for educators at pharmacy faculties for orientating students accurately about mental illnesses. Mental illnesses should gain more importance in pharmacy education not only to increase the positive behaviors of the students, but also to improve their counseling skills.