This study qualitatively explores the causes of Foreign Language Classroom Anxiety (FLCA) among Thai graduate students. Data were gathered through semi-structured interviews and focus group discussions with participants from various higher education institutions. Thematic analysis identified three central themes: Linguistic Competence Issues, Social and Relational Factors, and Emotional and Psychological Influences. Linguistic Competence Issues include challenges such as insufficient grammatical knowledge, limited vocabulary, poor pronunciation, and lack of practice, which undermine students' confidence and communication skills. Social and Relational Factors involve external pressures like teacher expectations, peer perceptions, and the fear of social judgment. Emotional and Psychological Influences encompass internal aspects such as fear of making mistakes, lack of self-confidence, and personality traits that exacerbate anxiety. The findings also reveal that students from private universities generally experience higher levels of FLCA compared to those from Rajabhat universities. This disparity is attributed to differences in institutional support systems, the diversity of student populations resulting from more relaxed admission criteria, and the presence of a more competitive academic environment. These findings highlight the complex nature of English language anxiety and underscore the importance of targeted interventions. By addressing these specific concerns, educators can enhance the educational experience for English as a Foreign Language (EFL).<p> </p><p><strong> Article visualizations:</strong></p><p><img src="/-counters-/soc/0770/a.php" alt="Hit counter" /></p>