Many concerns have been raised about the validity of the existing instruments measuring teachers' efficacy. Recently, a new instrument to measure teachers' perceived efficacy has been presented, namely, the Teachers' Sense of Efficacy Scale (TSES). The purpose of the present study is to examine the psychometric properties of the TSES in the Greek educational context. A total of 405 Greek secondary school teachers voluntarily participated in the study. A within-construct and between-construct approach was used to examine the validity and reliability of the Greek version of the TSES (factorial validity, internal consistency, temporal stability, and correlation with external criteria). Results are encouraging and seem to support the suitability of the TSES to assess teachers' efficacy within the Greek educational context. (Contains 2 tables and 1 note.)