High levels of apprehension cause students to have writing difficulties. This study attempted to identify the sources of Egyptian university students' English writing apprehension. The study made use of both quantitative and qualitative data. The scores of 57 students on a writing apprehension scale were compared to their scores on another scale assessing writing self-efficacy and three linguistic tests measuring English grammar and vocabulary. Additionally, 15 apprehensive students and 16 nonapprehensive students were interviewed about their writing experiences and beliefs. Analysis of the quantitative and qualitative data showed that there are six sources of the students' English writing apprehension: linguistic knowledge level, perceived language competence, writing performance level, perceived writing competence, instructional practices and fear of criticism. These results indicate the integrative nature of L2 writing ability and emphasise the need for dealing with these sources of apprehension. The study recommends that reducing L2 students' writing apprehension should start by improving their linguistic knowledge and writing ability; this will result in bringing about a positive change in their language and writing competence self-perceived beliefs. In addition, the study presents some other recommendations for improving instructional practices of English writing in the Egyptian context.