<p>Foreign language anxiety is among the most common issues encountered by English as a foreign language (EFL) learners. With the growing interest in mindfulness as an effective approach to mitigate stress and anxiety, this study investigated the effect of mindfulness on anxiety, under the moderating role of resilience, among Vietnamese learners in EFL classes. Students (<i>N</i> = 565) from various universities participated in a survey, in which they reported their level of mindfulness in everyday experiences, the degree of their anxiety according to different situations in English classes, and how they recover from stressful events. The measures included the Five Facet Mindfulness Questionnaire: Short-Form, the Foreign Language Classroom Anxiety Scale, and the Brief Resilience Scale. The results suggest that (1) there was a strong negative correlation between mindfulness and foreign language anxiety among the students, but mindfulness was a weak predictor of anxiety; (2) the relationship between mindfulness and foreign language anxiety was moderated by resilience; (3) there was no significant difference between male and female students in the levels of mindfulness, anxiety, and resilience. From the findings of the study, implications and recommendations for future research were discussed.</p>