While different models and questionnaires have been devised and used to measure learners’ willingness to communicate in a second language (L2 WTC), to date, few scales, if any, can be found to measure foreign language teachers’ L2 WTC (FLT WTC). Therefore, the current project was designed to address this gap in the literature through an empirical investigation of the factors affecting FLT WTC. Consistent with an inclusive review of the literature and expert panel consultations, a model of contributing factors to FLT WTC was hypothesized, a representative questionnaire was devised and went through Exploratory Factor Analysis and Confirmatory Factor Analysis. A large scale of 1044 foreign language teachers participated in different stages of the study. The statistical indices of the study confirmed that the model was fit and the questionnaire established appropriate levels of reliability, and face, content, construct, convergent, and discriminant validity. It was found that teacher perceptions, student traits, classroom atmosphere, classroom settings, and discussion topics play significant roles in FLT WTC. The study can draw the teachers’ / institutes’ attention to the factors affecting FLT WTC, and the validated questionnaire can be used as an instrument to measure FLT WTC in future studies