This study has investigated the relationship between IELTS testing and Omani English teacher trainees' professional competencies by adopting a quantitative method for data collection. A total number of 94 graduate freshmen Omani English teachers' IELTS, CGPA and their teaching professional competencies are collected. The results reveal a moderate significant relationship between IELTS and CGPA but a weak relationship between IELTS and teaching competencies. This study could contribute to the growing body of literature that aims to assess the construct validity of IELTS, and attempts to do so in the new terrain of teaching competencies. This study puts forwards recommendations for IELTS proficiency test in the Omani context.