A scale for measuring self-efficacy for teaching mathematics in grades 5 to 10 was developed in this study for teachers in Oman. The participants were 328 mathematics teachers randomly selected from five educational governorates in the Sultanate of Oman. Factorial structure of the scale revealed three subscales: self-efficacy for understanding the mathematics content, self-efficacy for teaching the mathematics content, and general teaching self-efficacy. The three subscales showed strong internal consistency and sufficient evidence of construct validity and concurrent validity. The scale has potential uses for both educational and research purposes.