Washback refers to the influence of tests on learning and teaching. To date, a number of studies have revealed that tests affect teaching content, course design, and classroom practices. However, in Asian higher education contexts, little research has examined the washback of proficiency tests on English learning in comparison with the efforts on teaching. Thus, the current study bridged this research gap by exploring the washback effects of a proficiency test on student learning in a campus-wide English curriculum, uncovering relationships between washback and learner characteristics such as major, gender, and proficiency level. A total of 694 students from engineering-, business-, and foreign language-related disciplines at a national university in Taiwan were surveyed. The results revealed washback effects on such aspects as personal image, learning motivation, emotion, and future job opportunities were especially salient. In addition, the relationship between washback and proficiency level was found to be statistically significant. However, male and female students did not differ statistically in washback nor was there a statistically significant difference in washback among different majors. With detailed information and consideration of different aspects of washback, stakeholders, including instructors, school administrators, and language policymakers, can make informed decisions when formulating language-related policies.