The purpose of this study is to investigate the difference between writing performance, writing-related beliefs, and quality of life between the underachieving children in writing and general children. The results are summarized as follows. First, in the amount of writing performance of children with underachievement in writing, there were differences in the total number of syllables, total sentences, and total vocabulary they generated compared to the general children. Second, children with underachievement in writing showed a different quality in the content, writing organization, and expressions used in their writings. Third, children with underachievement in writing demonstrated different levels of writing-related beliefs such as lower writing efficacy and implicit intelligence than those of the average-achieving students. writing efficacy and implicit intelligence. Whereas the underachieving students showed lower positive beliefs than their opponents, no significant difference was detected in the stereotyped beliefs among the two groups. Fourth, there was a difference in the quality of life which includes the self-essteem and subjective well-being as sub-factors between the two groups. The students with writing underachievement appeared to show a lower self-esteem and higher negative attitude on themselves compared to those with average achievement. Furthermore, the underachieving students in writing appeared to feel a lower subjective well-being than those of their opponents. Based on these findings, insights and suggestions for future research are discussed.