This study examines the links between early childhood teachers' attitudes toward STEM education, constructivist beliefs, and self-efficacy in STEM education. For this purpose, the study was conducted using a survey model. The study's participants are 211 early childhood teachers working in various regions of Turkey. The study collected the data through attitudes toward STEM education, self-efficacy, and constructivist beliefs scales. The data were analyzed by Pearson correlation, multiple linear regression, and path analysis. According to the results, a low positive correlation was found between attitudes toward STEM education, self-efficacy in STEM education, and constructivist beliefs. In addition, it was determined that traditional beliefs did not significantly affect attitudes toward STEM education. At the same time, self-efficacy in STEM education and constructivist beliefs significantly predict teachers' attitudes toward STEM education. Another finding determined that teachers' constructivist beliefs were a partial mediator variable in the relationship between self-efficacy in STEM education and attitude towards STEM education. The results provide perspectives on the links between teachers' attitudes toward STEM education, constructivist beliefs, and self-efficacy in STEM education.