This study investigated graduate-level international students’ linguistic and learning experiences in classrooms predominated by native English-speaking (NES) students. The central objective was to discern the impact of NES students’ presence on the fear of negative evaluation experienced by international students speaking English as a second language in an American university. A survey was initially administered to 22 graduate-level international students, and five international students, distinguished by heightened levels of anxiety associated with negative evaluation in classrooms primarily dominated by NES students, were interviewed. The interview data were analyzed with domain analysis. The findings elucidated that international students’ fear of negative evaluation depended mainly on instructors’ practices and international students’ perceptions of NES peers’ attitudes. Moreover, the increased fear of negative evaluation adversely impacted their linguistic behaviors and overall engagement with instructional content. The findings implied a need for more inclusive and safe learning environments in graduate schools.