In 2016, the Office of the Higher Education Commission issued a directive requiring all higher education institutions in Thailand to have their students take a standardized English proficiency test. According to the directive, the test's results had to align with the Common European Framework of Reference for Languages (CEFR). In response to this directive, this study was conducted to demonstrate how to develop such a test. Grounded in the conceptual frameworks of test usefulness, standardized tests, test development processes, and the CEFR, the study explored six stages in developing a 100-item-multiple-choice standardized English proficiency test: test planning, test design and writing, test reviewing, test piloting, test revising and revised test try-out. The test was piloted during the test piloting and revised test try-out stages with 108 and 88 students, respectively, and underwent item analysis to examine its reliability, difficulty index, and discrimination index. The item analysis conducted after the revised test try-out stage showed that the test's reliability, assessed by Kuder-Richardson Formula 20 (KR-20), was 0.94, suggesting that the test was highly reliable with good internal consistency. How the test was developed in close alignment with test usefulness and the CEFR is discussed in the study.