This study investigates the washback effects of the English High School Exit Examination (EHSEE) on the choices of learning contents and activities of non-English major 12th grade students in a public high school in Hanoi, Vietnam. The research aims to address the gap in washback studies regarding the EHSEE and high school students. A convergent mixed-method approach, utilizing a questionnaire and semi-structured interviews, was employed. Regarding learning contents, the findings reveal that the EHSEE had minimal positive washback on students’ choices. Additionally, students allocated more time to learning assessed areas, indicating negative washback as this may lead to students’ restricting their learning contents to prepare for the EHSEE. This negative washback observed in the study can also stem from the form-focused nature of the tested areas. Regarding students’ choices of learning activities, the EHSEE was found to leave no significant washback. This can be attributed to various factors, including the perceived difficulty of the test, students’ future study goals not requiring English proficiency, their usual test-taking habits, their perceived English proficiency, their personal circumstances, and the contents of textbooks. The findings underscore the complexity of how exams influence language learning, warranting further research.