From ancient times, both of Thai and Korean people have believed that dreams foreshadow the destiny and fortune of people and these beliefs about dreams have also been accepted in literature. The purpose of this study is to examine and compare the function of dreams as a literary device and folk beliefs through dream motifs and dream interpretation in KhunChang KhunPhaen of Thailand and ChunhyangJeon of Korea which are regarded as one of the most well-known classical literary works. A variety of dream motifs that are found throughout KhunChang KhunPhaen and ChunhyangJeon performs its function as episodic elements in the structure of narrative and also shows beliefs related to dreams well at the same time. Most of dream motifs in KhunChang KhunPhaen and ChunhyangJeon give some sign of foreshadowing about the characters’ fortune or events happening in the near future. Especially people in ancient societies of the two countries believed that if a woman becomes pregnant, she will dream about the birth of a child and it can be expected that the unborn child is male or female, how it looks or what kind of person it is when it grows up. Despite differences of interpreting the meaning of dream symbols due to different cultural and historical backgrounds, beliefs related to conception dreams are almost identical. As literature is a reflection of the times and is the mirror of the inner world of people, dream motifs in KhunChang KhunPhaen and ChunhyangJoen functions to inform the direction of a narrative structure and shows that Thai and Korean people in the traditional society have believed sanctity of dreams, dreams’ function of foresight and revelation of dreams firmly as well.