<p>Language proficiency tests significantly impact teaching and learning, commonly referred to as the washback effect, which has recently gained intense attention in China. This study explores the factors influencing the direction, timing, and intensity of the washback effect of the Chinese proficiency test (HSK). In this study, a mixed research method was used to study international Chinese language teachers and students through an ordinal logistic regression model and semistructured interviews. The findings reveal that personal, test, and environmental factors contribute to the washback effect. Notably, test factors exert a particularly strong influence on both teachers’ and students’ washback effects, whereas personal factors significantly influence only the washback effect of the HSK on students, and environmental factors significantly influence only the timing of the washback effect of the HSK on teachers. This study combines the examination characteristics of the HSK and international Chinese-language education scenarios; systematically verifies the influence of individual, examination, and environmental factors on the washback effect of the HSK; and expands and enriches the washback effect theory.</p>