The purpose of this study was to (1) explore the emotional vulnerabilities experienced by novice TAFL (Teaching Arabic as a Foreign Language) and TEFL (Teaching English as a Foreign Language) teachers when teaching in online classes and (2) investigate the emotion regulation strategies that they used to deal with the negative emotions. To such ends, we followed an explanatory narrative design to investigate the emotional vulnerability and emotion regulation strategies of ten novice TAFL and six novice TEFL teachers in their online classes. We collected autobiographical narratives and conducted unstructured interviews. The results of the reflexive thematic analysis showed that teaching in online classes led to experiencing both positive (curiosity, happiness, contentment, and satisfaction) and negative emotions (anger, anxiety, frustration, sadness, confusion, and fear) by novice TAFL and TEFL teachers. The findings also showed that novice TAFL teachers experienced more negative emotions compared to novice TEFL teachers. Moreover, the findings indicated that although novice TAFL teachers experienced curiosity as a positive emotion in their online classes, novice TEFL teachers did not experience this emotion. Concerning emotion regulation strategies, the findings indicated that novice TAFL and TEFL teachers used different strategies to deal with negative emotions. The findings concerning emotion regulation strategies also showed similarities and differences between novice TAFL and TEFL teachers. We conclude that emotional vulnerability caused by teaching in online classes might benefit TAFL and TEFL teachers. Moreover, emotion regulation has goals, and teachers might regulate their emotions at different time intervals in online classes. Finally, teachers' emotional vulnerability in online classes might be affected by the quality of L2 teacher education programs. As for the implications of the study, we suggested that L2 teacher education programs should create knowledge-based and practice-based venues for teachers to experience and deal with emotions before real classes.