Bipolar disorder, as a known disorder throughout the world, negatively affects people personally and socially. In addition, it leads to malfunction and dysfunction in their profession. To help bipolar people, a variety of approaches have been proposed among which positive thinking training can be mentioned. Moreover, professional identity is of importance in the quality of English as a Foreign Language (EFL) teachers’ teaching. This study, using a grounded theory design, aimed at modeling bipolar EFL teachers’ professional identity patterns before and after training on positive thinking. The participants consisted of 25 bipolar EFL teachers (16 males and 9 females) who were purposefully selected from EFL teachers teaching in private language institutes in Kerman, Iran. Bipolar Spectrum Diagnostic Scale and a semi-structured interview were used to collect the data. Concerning the results, a model was proposed wherein, before positive thinking training, the bipolar EFL teachers had a fear of teaching failure, did not emphasize students’ needs, used mainstream teaching methods, had the fear of being known as unknowledgeable, and had the fear of being known as irresponsible and unaccountable. However, after positive thinking training, the bipolar EFL teachers had good communication, classroom management, and motivational skills, were more willing to reach professional development and more proficient in the English language, used the best teaching methods, and had good verbal skills. The findings have some implications for EFL teacher education administrators and bipolar EFL teachers. Manuscript profile