This study aims to examine the contributing factors of public speaking anxiety (PSA) among international and Malaysian postgraduate students. To realise the study, a Personal Report of Public Speaking Anxiety (PRPSA) and Foreign Language Communication Anxiety Scale (FLCAS), were employed through a qualitative research design. Three postgraduate students were chosen according to a selective sampling method and interviewed using semi-structured interview protocol. The interview questions were adopted and customised to adhere to a situation specific setting, which is the online learning domain. Results indicated that fear of negative evaluation and making errors along with peer pressure were among the main reasons for PSA. It was also found that PSA had a significantly negative influence on some postgraduates' online learning performances while having a moderate effect on some other postgraduates. This research is significant to understand the causes of learners' PSA, foreign language anxiety and the relationship between speaking anxiety and academic performance.