Abstract The issue of English as a Foreign Language (EFL) teachers’ professional development (TPD) which is mainly about instructors’ learning has been the foci of many studies. However, individual development planning (IDP) which is known to be an assessment tool in the TPD cycle has remained untouched. The so-called instrument enables the individuals to reflect on their past performances, identify their training needs, and plan for their future development accordingly. In an attempt to contribute to the richness of this lacuna a mixed-method study was carried out in 3 distinct stages. Qualitative data were collected from 17 expert participants through semi-structured interviews followed by 380 Iranian EFL teachers answering the researcher-made questionnaires in the quantitative stage of the study. In the first phase of the research, EFL teachers’ duties and tasks along with their educational needs were explored through DACUM workshops. Then, related questionnaires were designed based on the obtained themes and the data gathered underwent SPSS software which showed the most and the least important concepts. In the second stage of the study, EFL teachers’ IDP was investigated in the framework of grounded theory and factors affecting it were identified. Then, a conceptual model was proposed based on the categories and sub-categories achieved. In the third stage, the fitness of the model was measured through SEM. The results obtained in the first stage of the study helped the researchers identify the basic duties, tasks, and educational needs of EFL teachers firstly through qualitative and secondly quantitative analysis. The results of the second stage’s analysis led to a conceptual model of EFL teachers’ IDP along with the factors having an impact on this phenomenon. The results of the third stage yielded fitness of the already developed model through SEM by the use of SmartPLS software. The findings of this research have both theoretical and practical implications for the TEFL domain. Theoretically speaking, EFL teachers’ professional development, especially IDP, would be enriched by the categories drawn, the validated model, and the questionnaires developed. From a practical point of view, these findings can pave the way for the improvement, training, and evaluation of EFL teachers at school. Key words: EFL teachers, Teachers’ professional development, Individual development planning, Developing a curriculum, Structural equation modeling.
