This study aimed to develop a second-language willingness to write (L2WTW) model for foreign language writing classrooms. For this purpose, based on previous empirical studies, a hypothesized framework that describes the relationship between L2 motivation, L2 learners' attitude, autonomy, self-confidence, teacher/peer feedback, and knowledge of genre and L2WTW were proposed. Then, the model, which integrated a mixture of psychological, cognitive, textual, and contextual variables, was tested by using structural equation modeling (SEM). One hundred and ninety-five upper-intermediate English major university students were selected and were asked to complete a questionnaire. The results revealed that there were positive relationships between teacher/peer feedback, autonomy, L2 motivation, L2 learners' attitude, and L2WTW. However, this study did not find a significant relationship between knowledge of the genre and L2 writers' self-confidence and L2WTW. An implication of this study is that English language teachers can employ the investigated variables to increase their students' L2WTW.