Past study has shown that second language acquisition is equally important as second language learning. Second language acquisition is the subconscious process of absorbing the second language knowledge, and it happens automatically when the students are exposed to the use of the language around them. This study aims to identify the factors affecting second language acquisition among boarding school students and how they acquire the language. The participants were students in one of the boarding schools in Peninsular Malaysia. The data were collected through semi-structured interviews. The findings demonstrate two factors affecting second language acquisition among boarding school students: intellectual process and mother tongue influence. Of the two categories, intellectual processes are the most dominant factors in which are the two major contributing factors affecting second language acquisition among boarding school students. This study implicates the importance of second language acquisition in driving proficiency and enhancing the learning process among boarding school students.