Teaching thinking skills is core of the curriculum in many cultures. Although curricula have mutual points, the results were different from each other. Having different results of teaching thinking curriculums applied in different countries indicates importance of personal differences of teachers. Defining level of teacher's self-efficacy makes a contribution to determining success level of curriculum. Developing a global scale contributes both researchers and practitioner while teaching thinking. The aim of this study is to adapt Teachers' Self-efficacy towards Teaching Thinking Skills Scale (TSTS), developed in Turkish, into English. The scale consists of 20 items. Each item has 5 point Likert type. It has 3 factors as Design, Practice and Academic Competence. For this purpose, firstly linguistic equivalence was analyzed. For linguistic equivalence, both versions of the scale were applied to 28 candidate teachers of English with 20 day intervals. In the second step, Confirmatory Factor Analyses was administrated to data taken from 144 native English teachers. After the analysis, good level fitting indices were found. Cronbach Alpha coefficient value is .94. Construct validity (Convergence and Discriminating validity) study on correlations between sub-dimensions and average explained variance value has good sufficient level. Scale items were found discriminating. Results showed that English version of the scale was statistically valid and reliable.