In Turkey, the “Museum Education Certificate Program” was launched in 2019 in cooperation with the Ministry of National Education and the Ministry of Culture and Tourism, and within the scope of this program, museum training was given to thousands of teachers from different branches. Within this framework, the purpose of this study is to display the self-efficacy beliefs of teachers who completed museum education formateur or trainee training. This study, which employs survey model, a quantative research method, the sample constitutes 102 teachers working in various branches of different education levels, who voluntarily participated in the study. Self-Efficacy Scale for Museum Education was used as a data collection tool in the research. The data were statistically analyzed and interpreted with SPSS 16.0 program. As a result of the study, it was found out that teachers who received museum education had high levels of self-efficacy beliefs. However, it was concluded that those who received education as formateur had higher levels of self-efficacy compared to those who received education as trainee. Based on the findings, it has been recommended that in-service training activities for museum education should be continued with expanded coverage.