This study attempted to explore the effects of partners' proficiency levels on test scores in paired English speaking test. Although the influence of interlocutor's effects on speaking test performance has been extensively researched in the previous studies, the findings have been inconsistent. The present study explored the effect of partners' proficiency levels on test scores in a paired speaking test. Participants included a total of 107 female adults and college students. Based on their standardized speaking test scores, they were grouped into five levels: Superior, High, Intermediate, Novice-high, and Novice proficiency level. Then, 90 test takers completed the test three times with being paired with three different partners. The partners' proficiency levels were higher, the same as, or lower than their own. The results showed an increase in test scores, as the proficiency level of the partners is higher. Furthermore, a statistically significant differences were found in the test scores of test takers. In light of such effects, these findings indicate that the validity of paired speaking test needs to be reconsidered its use and to find a better way to utilize it in a larger context.