This study aimed at investigating the level of context-based communication apprehension (CA) among Rajamangala University of Technology Lanna (RMUTL) Phitsanulok students in their EFL classes, and the factors that contributed to the emergence of CA among the said students in different contexts. This study was conducted with the aid of 281 students in three different faculties, the Faculty of Business Administration and Liberal Arts (BALA), the Faculty of Engineering (ENG), and the Faculty of Science and Agricultural Technology (SAT) as respondents. A set of questionnaires was employed to gather data from the students, and they were statistically analyzed quantitatively and qualitatively. Results revealed that students in EFL classrooms experienced an average level of context-based communication apprehension. Furthermore, evaluations of self and others, and error-related issues surfaced as the highest factors that contribute to the emergence of the communication apprehension of Thai EFL students. The main reason why students tend to experience anxiety in an EFL classroom was that they think that they were not well versed in English. Furthermore, they shun speaking situations in an EFL classroom because they think that they may be laughed at or judged by their classmates or peers when they commit some mistakes when speaking in the English language. It should be taken into consideration that when students have lesser exposure to English, the students may tend to experience more CA. Faculty and types of English teachers recorded direct effect on the communication of Thai EFL students. Cognitive restructuring was one recommended technique and used by some students to lower their CA.