This paper reports and discusses how the IELTS test has brought its impact to Assumption College Thonburi English Program (ACTEP)'s exit testing, English courses offered and foreign teachers' teaching. Two different methods of data collection apply; an interview with the ACTEP Academic Head and questionnaire for Grades 10-11 students and foreign teachers. It has been found that in order to assure Grade 12 performance on the IELTS test, other well-known achievement tests have been put into the ACTEP academic policy. IELTS preparatory courses have been listed into the Grades 10-12 ACTEP curriculum. The findings show that the foreign teachers, both Native-English speakers and Non-Native English speakers teaching staff in the ACTEP, need more insights to the IELTS test format. It is also well worth recommending that students need to practice more during their high school years as their Grade 11 exit test, the CU-TEP test, cannot reflect all strategies needed in the IELTS test.