Since teachers’ perceptions of work engagement can strongly shape their engagement level, it is imperative to explore how teachers perceive this construct and its associated dimensions. With this in mind, some researchers have evaluated teachers’ beliefs and attitudes towards this notion. Notwithstanding this, to the authors’ knowledge, no study has examined language teachers’ viewpoints on this variable and its significance in online EFL classes. To bridge these gaps, this phenomenological study explored Iranian EFL teachers’ perceptions and experiences of work engagement and its value in online English courses. To this aim, using the purposive sampling strategy, a total of 21 EFL teachers were chosen from different state, private, and non-profit universities in Iran. To obtain the required data, all participants were invited to complete an open-ended questionnaire. To reach more comprehensive data, from among the 21 participants, nine willingly took part in a 20-minute interview session. Results obtained from content analysis revealed that Iranian EFL teachers considered work engagement as a complex variable with four related dimensions of emotional, cognitive, behavioral, and social engagement. The results also indicated that Iranian teachers perceived work engagement as an important professional behavior that results in increased academic achievements, professional advancement, improved teaching quality, and strong teacher-student rapport. Hence, education leaders and teacher educators should support Iranian EFL teachers in enhancing work engagement dimensions to improve professional growth and teaching quality.