Abstract This study investigates Chinese university EFL teachers’ and students’ beliefs about what determines the text quality of EFL writing via a mixed-method analysis of data collected by questionnaire, interview, and diagnostic and self-diagnostic feedback on students’ essays. The results indicate that: First, both the teachers and students attached much importance to language, but the teachers put significantly more emphasis on organization and content whereas the students put significantly more emphasis on vocabulary; Second, the beliefs of students were heavily influenced by their conceptions of the purposes of EFL writing tasks and the assessment criteria adopted to mark their writing; Third, the disparity between teachers’ and students’ beliefs caused them to emphasize different aspects of an essay when giving feedback; Finally, students’ beliefs had a negative impact on the development of effective writing strategies. Pedagogical implications are suggested.