A project in Thailand to develop domain-referenced English language tests for use with Thai secondary and college students is described. The first phase consisted of developing standardized tests for listening, speaking, reading, and writing based on existing syllabuses, determining the common levels of English proficiency in those domains, and analyzing the communicative competence factors in English use of the Thai students. Subjects were 697 lower secondary, 525 upper secondary, and 493 university students. The second phase involved examining the consistency of domain specifications and setting domain-content standard scores for the tests. The process of test construction and validation are outlined, and results for each phase are reported. Recommendations for further research in this area include study of the contribution of individual language skills to the development of overall language proficiency, with the objective of finding effective remedial methods, and similar test and standard development for all levels of Thai education. Recommendations for practical application in English teaching and learning include use of a communicative context for language instruction and early emphasis on oral/aural skills gradually leading to later emphasis on reading and writing. A 55-item bibliography and test objectives, specifications, and analyses are appended. (MSE)