Writing in L2 is a complex phenomenon in which affective factors play an important role. Among others, demotivation can determine the students' success in orchestrating the complex writing processes and the quality of their L2 writing texts. Although there is a growing body of research investigating demotivating factors (e.g. teacher, self-confidence, materials and methods) in language education, there is a scarcity of research on L2 writing demotivation. This two-phase study is an attempt to develop and validate a writing demotivation scale. To this end, a total of 551 EF L students participated in the development phase, and a total of 367 EF L students were recruited for the validation phase of the study. An EFA was employed to determine the factor structure of the scale. The results of the EFA revealed a five-factor solution with self-perceived L2 writing competence, teacher practices, attitudinal aspects, writing materials and methods, and teaching/learning context In the validation phase, a CFA was performed. The results of the CFA showed that the model fits the data well. Overall, the English Writing Demotivation Scale (EWDES) is psychometrically a reliable and valid instrument that can be used for investigating the L2 writing demotivation.