The authors examined the factor structure of the long and short forms of the Teachers' Sense of Efficacy Scale (TSES; M. Tschannen-Moran & A. Woolfolk-Hoy, 2001) for practicing (n = 102) and preservice teachers (n = 270), comparing the responses to both forms of the TSES, and looked for differences in teachers' efficacy with respect to experience and grade level taught. They found the 3-factor structure--efficacy for classroom management, instructional practices, and student engagement--to be appropriate for practicing teachers, but they found a single efficacy factor to be appropriate for preservice teachers. The long and short forms of the TSES produced similar means and reliability information, suggesting that either form is appropriate for use with preservice or practicing teachers. Last, they found that teachers with 10 or more years of teaching experience and those teaching at the elementary level reported significantly higher levels of efficacy than did preservice teachers or those teaching at the middle or high school levels, respectively. (Contains 5 tables.)