English is a global language and is used in educational institutions in English and non-English-speaking countries. The quality and effect of English as a Foreign Language (EFL) instruction at the undergraduate level in Saudi Arabia is a kind of challenge for the students as well as the teachers. It is a fact that English is an internationally intelligible language and is used as a lingua franca in Gulf countries where expat teachers and students have different L1 (native language) and use English to communicate with each other. Taking EFL undergraduate students into consideration, English is the language which helps them to convey their message to the instructor and vice versa, particularly in an atmosphere where the instructor is not Arabic. English is a common means of communication. A majority of people show an interest in learning English in order to communicate on an international, professional level. The basic function of English is communication. Speaking English allows one to opt for foreign universities and an opportunity to work abroad where English is spoken. This piece of work focuses on the use of English as a medium of instruction in the English classes of undergraduate EFL students in Saudi Arabia and the communication problems faced by both the teachers and the students. The paper also discusses the perceptions or points of view from both teachers and students towards giving preferences for using English, Arabic, or both and their frustrations and positive responses towards using English as a medium of instruction. The data was collected from 50 participants, of whom 30 were students and 20 were teachers. Undergraduate students and their English teachers responded to a questionnaire which was administered to know their perceptions about using English as a Medium of Instruction and the effect of the Arabic on their English. The paper finally discusses some solutions according to the data perceived by teachers and students for using English as a medium of instruction and also gives some recommendations which will improve their English learning skills at an early stage.