This paper examined the influence of L2 on L3 accent and fluency. Target participants were native speakers of Chinese who have studied English as an L2 prior to beginning their study of Japanese as L3. Participants were recorded in L2 and L3, and their speech samples were rated by expert judges of respective language. The judges were asked to rate each speaker based on foreign accentedness and overall fluency. The results from English and Japanese were analyzed using correlation analysis. The result of the correlation analysis showed a positive correlation between accent in L2 and L3, which suggests that, regarding foreign accentedness, the better a speaker performs in L2, the better they also perform in L3. The correlation between L2 and L3 in terms of fluency did not reach significance, mostly due to the fact that fluency rating in English was done mildly by the judges. The result nevertheless showed a clear trend toward positive correlation between the two languages. This study contributes to the area of Third Language Acquisition by supporting the idea that L3 acquisition is qualitatively different from L2 acquisition, and phonological acquisition in L3 is influenced not only by the learner’s L1 but also their L2.