Objective: This study aimed to assess the impact of mental health literacy education on the beliefs and attitudes of family physicians in Turkey regarding mental illnesses. Method: This study, conducted using a pre-test post-test experimental design with experimental and control groups, involved 461 physicians from 95 Family Health Centers in Kayseri, Turkey. Both experimental and control groups were administered pre-tests, followed by online mental health training for the experimental group, and then post-tests were conducted. Data were collected using the "Personal Information Form," "Mental Health Literacy Scale," "Beliefs toward Mental Illness Scale," and "Community Attitudes toward the Mentally Ill Scale." Results: Data from 184 physicians were analyzed, the educational intervention significantly improved mental health knowledge (p=0.032), help-seeking adequacy (p=0.043), and positive attitudes (p=0.032), while reducing perceptions of danger (p=0.043) among the intervention group. The study indicated significant enhancements in mental health knowledge and help-seeking adequacy among primary care physicians in Turkey following online mental health literacy education. However, its impact on beliefs and attitudes towards mental illness is comparatively modest. Further research is necessary for a deeper analysis of the relationships between these dimensions. Discussion: Mental health literacy education positively influences primary care physicians’ knowledge and help-seeking behaviors regarding mental illnesses, although it has a relatively modest impact on their beliefs and attitudes. There is a need for further research to conduct a more in-depth analysis of the relationships between the dimensions of beliefs and attitudes towards mental illnesses in mental health literacy education.