This review synthesizes the findings of research compiled between the relationship on international student success and the International English Language Testing System (IELTS). Increasingly, within higher education, IELTS test scores have become not only a benchmark for testing the language proficiency of international students who speak English as an additional language, and subsequently their entry into higher education institutions, but also a presumption of student academic learning success. A growing concern for many higher education institutions is that proficiency in English does not necessarily equate to international students' preparedness to study at the higher education level with regards to their academic learning success. Amidst growing ambivalence related to the use of IELTS as a placement tool, this literature review outlines three main themes found in connection to the correlation between IELTS and international students' academic learning success at the undergraduate level. The first two themes focus on the positive and negative correlations between IELTS scores and international students' academic learning success. The third theme is related to a social dimension which focuses on the fact that, for international students, linguistic proficiency is linked to how they adapt to their new learning and living environments. Here the relationship between IELTS as an indicator of students' preparedness for the rigours of academic study is being explored. The review ends with a short examination of published documents by IELTS. Overall, this literature review suggests that a common theme found in the published research is that even with a high IELTS score, international students do need academic support when studying at the higher education level.