This study investigates the use of passive voice in online English writings composed by EFL students at some member universities belonging to the University of Da Nang, Vietnam. The study result is in line with the findings of previous studies which suggest that passive voice occurrence is less dominant than active voice in both traditional and online English academic writing; However, it finds the number of passive voice patterns appearing in their final version tends to increase in comparison with the initial version considerably. In addition, this study discovers that the higher the students' English levels, the less bias in using passive voice in their online English writings. Particularly, the more technically specialized the topic is, the more passive patterns going with the verb ‘be’ occur in their papers.