The purpose of this study is to contrast Japanese ‘koto/no’ and Korean ‘kes’ clauses in order to clarify their similarities and differences. ‘koto/no’ in Japanese ‘koto/no’ clause and ‘kes’ in Korean ‘kes’ clause, they serve as complementizers to form embedded noun clauses in Japanese and Korean. Since these are originally dependent nouns, we first analyze the features of the dependent nouns ‘koto/no’ and ‘kes’. Secondly, we contrast the ‘koto/no’ embedded noun clauses and the ‘kes’ embedded noun clauses, which are used as obligatory arguments for the verb of a matrix clause. In contrast, there are unusual ‘no’ and ‘kes’ clauses that seem to be embedded noun clause of the verb of a matrix clause in Japanese and Korean, therefore, we contrasted ‘no’ and ‘kes’ clauses. This study contrasts the similarities and differences between the Japanese ‘koto/no’ and the Korean ‘kes’ clauses, which are similar markers of grammatical functions in Korean and Japanese, namely, dependent nouns, which are originally grammaticalized and serve as complementizers to induce clauses. This study will be helpful both to teach Japanese as a foreign language and Korean as a foreign language.