The purpose of the study was to compare the instructional effectiveness of bilingual instructors compared to monolingual instructors. The case study design was non-experimental using a mixed methods approach. The data was collected from surveys, interviews, and classroom observations of monolingual and bilingual instructors (n=120) at a private university in Saudi Arabia. The survey and interview results showed bilingual instructors in favor of the bilingual method while monolingual instructors were not. Classroom observational data showed more incidents of student engagement recorded in the bilingual instruction compared to the classrooms where monolingual instruction took place. The implications of the study demonstrate the need for a policy change to allow bilingual instruction in the classroom and for preference given to the hiring of bilingual instructors as a means to facilitate student understanding of concepts in the classroom and in empowering second language acquisition of native Arabic speaking students.