This study examines how Vietnamese high school leaders interpreted and implemented policy changes of the Vietnamese National High School Examination--a nationally standardized exam that determines whether students may graduate from high school and attend post-secondary education. The research found that at the national level, the policy is highly prescriptive, with expected uniformity and fidelity in implementation; however, at the same time, it is vaguely worded and inconsistent. At the local level, how school leaders interpreted the new policy varied according to their knowledge, experiences, values, and beliefs, making their implementations deviate from the original policy's intent. Their policy interpretation and implementation were also shaped by systemic inequities in academic rankings and educational resources of schools that they led.