The purpose of this research is to explore more efficient methods of language education by performing comparative analysis on syntactic errors that learners make in the Korean language and the Thai language. The research results showed that in the case of the Korean students learning the Thai language, lexical errors and grammatical errors were found to be made at a similar rate. But in the case of the Thai students learning the Korean language, far more grammatical errors than lexical errors were found to be made. This is considered to be caused by the fact that the Korean language has the characteristics of both agglutinative language and inflectional language and its grammatical system is complex to a certain extent. In the lexical errors, both the cognitive errors in the language to be learned and the mother tongue interference errors were found, and it is necessary for the Korean students learning the Thai language to intensively study by preparing the list of Thai words whose meanings are similar or frequently mistaken. Meanwhile, the Thai students learning the Korean language need to study the postpositional particles and inflection of the Korean language intensively. Also, the learners of the both countries need to be familiar with the word orders of modifiers and modificands, which are different from that of mother tongue. Aside from this, the Thai students who learn Korean need to be familiar with the passive expressions of the Korean language that Korean people frequently use in their daily life, and the Korean students who learn Thai need to pay more attention to the causative expressions of the Thai language that Thai people frequently use in their daily life.