This study aims to develop a valid and reliable scale to measure teachers' self-reported job performance and use it for the first time on the target group. In line with this aim, the current study employed a single surveying model. The study sample consisted of three groups. There are 265 teachers in the first group; 509 teachers in the second and 1935 teachers in the last one. Exploratory factor analysis and confirmatory factor analysis were used to determine the factor structure of the teachers' job performance scale (TJPS). Cronbach's Alpha reliability coefficient and item statistics were also calculated. Results showed that the TJPS is a valid and reliable three-dimensional measure: task performance (16 items), contextual performance (9 items) and adaptive performance (12 items). On the other hand, teachers' performance level is "always" for task, adaptive and the overall scale and sometimes for contextual performance. Based on the findings, some suggestions were made.