This study compares the psychometric properties of two popular teacher self-efficacy scales, namely, Teachers' Sense of Efficacy Scale (TSES) and Teacher Efficacy Scale (TES). This study was quantitative in nature and distributed the two scales to 287 preservice teachers in the USA and in Australia. Findings indicate that the two scales function well and show linear measurement properties after Rasch optimization. However, the TES's factor of general teacher efficacy was found to have very low reliability. Regression analyses indicated a significant positive relationship between the Student Engagement subscale of TSES and TES. There is a limited relationship between the two popular scales that have been used for decades. Therefore, we argue for the need for a new scale that will reflect all components of Bandura's Triadic Reciprocal Determinism.