In recent years, there has been an increasing tendency for educational institutions and EFL instructors to integrate social media platforms in English language learning environments. The hypothesis is that social media platforms, including Facebook, Twitter, and Telegram, have positive impacts on the development of reading, writing, and communication skills, as well as the vocabulary development of EFL students. Despite the prolific literature on the effectiveness and usability of social media platforms, including Telegram, in EFL contexts, very little research has been done on the impact of Telegram Messenger on language development in general and the vocabulary development of ESP students. Thus, this study explores EFL law students' views of the usability of Telegram Messenger in a Telegram-supported legal terminology course. This quantitative study applies convenience sampling and adapts Kusuma and Suwartono’s (2021) survey questionnaire to collect data. The findings reveal a multi-faceted and very clear picture of Telegram Messenger as an informal form of virtual learning media. The findings confirm that Telegram Messenger is a very beneficial and effective tool, as demonstrated in the legal terminology course. Students express satisfaction with Telegram Messenger due to its easy accessibility and flexible use. They have positive attitudes concerning the educational applications of Telegram Messenger, especially in establishing learner–learner and lecturer–learner types of interaction and keeping them updated with lectures and examination-related issues. Telegram Messenger assists students in catching up with the lectures they cannot attend due to unfavorable circumstances.