The present mixed-methods study investigated the factors that build Iranian bilingual Azeri-Persian English as a foreign language teacher resilience (TR) in non-profit and state schools. To do so, 205 male and female teachers selected through snowball sampling from several schools in different regions of Iran participated in this study. In the quantitative phase, the Connor and Davidson resilience scale (CD-RISC) was utilized to measure TR. First, the factor structure of the scale was ensured through testing confirmatory factor analysis (CFA). Results indicated that all the five factors of TR tested by the CD-RISC were evident among all the respondents, and there were no significant differences between the factors building TR in state and non-profit schools. For the qualitative phase, 26 male and female teachers selected through purposive sampling participated in semi-structured interviews which were thematically analyzed through MAXQDA software. The findings revealed that while state school teachers perceived satisfactory curriculum and policies and consulting with colleagues as the building factors for TR, non-profit school teachers highlighted teacher training courses, teacher-student rapport, and students' progress as the important factors. The pedagogical implications of this study for teacher education are explained.