The purpose of this article is to investigate differences in complaints between Japanese native speakers (JNS) and Korean native speakers (KNS). This study examines how complaints are expressed in everyday situations based on data from a discourse completion test (DCT) which consists of 15 simulated situations. Upon comparing complaint expressions by JNS and KNS in each situation, a difference was found between complaint strategies and expressions used by JNS and KNS to express complaints. Furthermore, the analysis revealed a difference between the external modifications used by JNS and KNS.