This study examined mathematics teaching efficacy and its association with preservice teachers’ passion for teacher preparation and their overall teacher efficacy. In order to understand the impacts of preservice teachers’ passion for teaching and teaching efficacy on their subject-specific teaching efficacy, mathematics teaching efficacy, this study analyzed the data collected from 193 early childhood preservice teachers at a university in the Midwestern United States. Pearson’s correlation and hierarchical regression analyses were performed using SPSS 25. The results revealed that the preservice teachers were highly efficacious about their mathematics teaching, showing a positive relationship to harmonious passion and personal teacher efficacy. Harmonious passion for teacher preparation was the most significant predictors of their personal mathematics teaching efficacy. The results implied that harmonious passion had a significant influence on early childhood preservice teachers’ mathematics teaching efficacy, with low and high teacher efficacy leading to a higher mathematics teaching efficacy. This study discusses implications to enhance preservice teachers’ mathematic teaching efficacy.