Introduction: This study investigates L2 writing anxiety among Algerian EFL Master's students, focusing on anxiety levels, types, causes, coping strategies, and the effects of gender and proficiency. Methods: A mixed-methods approach was used, incorporating a semi-structured interview alongside two instruments: the Second Language Writing Anxiety Inventory and the Second Language Writing Anxiety Reasons Inventory. Participants included 220 Master's students selected through stratified random sampling. Results: Most students exhibited moderate to high writing anxiety, primarily cognitive and somatic. Gender differences were minimal, but lower-proficiency students reported significantly higher anxiety. Avoidance behaviours were the least reported. Discussion: Linguistic concerns, fear of evaluation, and time constraints were major anxiety triggers. Unlike prior studies, teacher influence was not a primary factor, though students desired clearer feedback. Coping strategies included self-regulation, brainstorming, and seeking peer and teacher support. Limitations: The study focused on Master's students, limiting generalizability to other proficiency levels. Self-reported data may also introduce bias. Conclusions: Providing structured feedback, supportive teaching strategies, and targeted language development can reduce anxiety and enhance students' writing confidence.