This study aimed to examine the factors affecting foreign language anxiety (FLA) in Chinese tertiary EFL classrooms. This study adopted a descriptive case study design involving 490 EFL students from one public university in China. Data were collected via a self-reported questionnaire and semi-structured interviews. The findings reported a moderate level of FLA among the students. Internal and external factors affected the student’s FLA, including performance anxiety, perceived lack of proficiency, low motivation, relationship challenges, and learning environment-related challenges. These findings implied universities should enhance the physical and pedagogical learning environment to sustain quality EFL teaching and learning.