The present study aims at investigating the effectiveness of the process-oriented writing approach in reducing Moroccan EFL students’ writing anxiety. It examines the three dimensions of writing anxiety namely behavioural, cognitive and somatic, unlike previous studies that dealt with it as a holistic entity, which adds more layers to EFL writing research and instruction. To this end, the participants were divided into two groups, experimental and control. For six months (two hours per week), control group students received academic argumentative writing instruction following their normal writing classes, while experimental group students were taught academic argumentative writing based on the process writing model. To collect the relevant data, all participants were asked to fill in Cheng’s (2004a) second language writing anxiety inventory before and after the treatment. The analysis of the collected data revealed that the experimental group participants showed notable lower mean values of somatic and behavioural anxiety after the treatment than the control group subjects, which provides evidence that the process-oriented approach is effective in reducing EFL writing anxiety. In the light of these findings, some pedagogical recommendations were suggested.