Writing is a challenging and demanding skill for EFL learners in Vietnam. Teaching writing skills at Vietnamese universities is problematic since different approaches to writing have not been implemented effectively. Mainly, a genre-based approach to writing has not yet been implemented in EFL writing classrooms successfully. This paper investigates how the genre-based writing approach has been taught and learned at Van Lang University. The study mentions some critical notions ofsystemic functional linguistics, genre-based writing approach, and the importance and effects of genre-based approach to writing. 128 students turned in their midterm essays in week 5 of the 10-week writing course. These 128 expository essays were analyzed and synthesized using Microsoft Excel to calculate the differences in move-step structure. The findings indicated that the students had difficulty following the fixed move-step structure, and they also faced challenges of lexico-grammatical usage for the expository. Hence, the study suggests some implications for applying a genre-based approach to writing for EFL teachers and students and suggests further research.