This study sought to investigate foreign language (L2) writing anxiety of Turkish students learning English as a foreign language (EFL) by focusing on the L2 writing anxiety levels; the prevailing types, perceived causes and effects of L2 writing anxiety; and the strategies that students employed to alleviate L2 writing anxiety. The study adopted a convergent parallel mixed-methods design consisting of a quantitative survey and qualitative open-ended interviews with the students studying at English Language and Literature undergraduate program at a state university in Türkiye. A total of 138 students responded to the questionnaire and eight volunteers among them were interviewed face to face. The survey data were analysed through descriptive and inferential statistics while interview records were analysed through thematic analysis. The findings converged on the point that the students displayed high levels of L2 writing anxiety and that time constraints and assessment orientation were the prominent factors leading to anxiety. The students’ L2 writing anxiety varied significantly across perceived L2 proficiency levels, demonstrating higher-level anxiety for the students reporting themselves as less proficient L2 users. Based on the interview reports, the student-perceived causes and effects of writing anxiety as well as the factors and relieving strategies were identified. Finally, recommendations for more effective strategies for alleviating English language learners’ L2 writing anxiety were discussed.