The concern over test consequence has inspired research into the wider impact of language tests and testing policies, but few studies have examined this subject in the context of Taiwan. With the goal of enhancing Taiwan’s global competitiveness by upgrading manpower quality, the central government implemented a 2002 policy to develop the English proficiency of civil servants by recognizing passing marks on approved English language proficiency tests as a promotion criterion. This thesis reports on a research study that adopted a multi-method approach to assess the testing policy’s impact on test-takers and analyze the rationale and consequences of revisions to the policy that were implemented between 2002 and the 2011. A survey of 282 civil servants working in the banking, economics, and finance sectors yielded data about the participants’ self-assessment of their English proficiency and workplace need for the language, English study and test-taking experience, impressions of English proficiency tests, and assessment of the effectiveness of the testing policy. Statistical analysis of the test impression and policy effectiveness data revealed significant correlation between positive assessments of the policy’s impact and the perceived fairness of the testing policy, the policy’s influence on motivation to study English, and the participants’ intrinsic interest in improving their English. Interviews with officials involved in formulating and implementing the testing policy and a review of government documents related to the policy provided data that were incorporated into the Geelhoed-Schouwstra policy analysis framework and facilitated the identification of factors that influenced the outcomes of the testing policy. The results of this study of an English language testing policy help to clarify who the test-takers and test users are, how and why tests are being used, and what the consequences of test use are.