This research was conducted to measure Persian EFL students’s degree of willingness to write in English. To reach the goal, semi-structured interviews were conducted, deriving inspiration from earlier works of McCrosky and Baer (1985), MacIntyre, Dornyei, Clement, and Noels (1998), and Yashima (2002) on willingness to communicate. The participants of the study were 29 individuals comprising 23 university students from different majors and 6 writing experts with academic statuses varying from BA holders in TEFL to university professors in applied linguistics. They were interviewed in two separate layers via employing the Delphi technique. Content analysis was conducted on the interviews and the components were extracted; the WTW questionnaire was then designed and developed for the first time and was validated via conducting factor analysis and was then administered to 257 university and IELTS students. The final version of the questionnaire included 38 items after having been factor analyzed. The results indicated that there are four factors underlying the construct of willingness to write, which are interlinguaprofession, cognition, involvement, and technology. The findings of the study can bring considerable benefits to EFL students to recognize the influential factors on their degree of willingness to write (WTW) and try to boost the facilitating factors to become more autonomous learners. Academic EFL/ESL writing teachers can enhance their students’ writing ability via embarking upon new strategies through which they can make learners more willing to write by promoting learners’ involvement and engagement in writing, as one of the findings of this study.
