Learning English has increased its popularity exponentially thanks to global needs in numerous fields. Accordingly, various means of instruction have been adopted to master English. English-only instruction, the alternative to code-switching, is one of them that urges educators and learners to communicate through English. Although many studies have examined the effectiveness of English-only instruction, a gap has been observed in the literature regarding students’ opinions at a tertiary level in the Iraq context. To this aim, 50 students who studied at TISHK International University’s Language Preparatory School in the 2022–2023 Academic Year were chosen via snowball sampling. Participants evaluated English-only instruction in terms of the overall program, instructors, and administration. The primary instrument used to collect data was a survey. Collected data, analyzed by SPSS 26 and NVivo, respectively, unearthed that English-only instruction received favorable feedback in terms of holistic English mastery, creativity, motivation, and time management. However, some communication barriers, thereby having low learning rates were cited by a few students as weaknesses of chosen instruction. Likewise, the instructors’ efforts to teach English through Web 2.0 tools, practice exams, real-life examples, and principles of student centered approach were appreciated without leaving any room for hesitation. Similarly, the administrators’ initiatives to guide, form, monitor, examine and take appropriate action to promote the quality of education with an English-only policy received positive feedback. The findings of this study may have certain implications for stakeholders who are interested in the implementation of English-only instruction at their institutions on a global scale.