Objectives The purpose of this study is to suggest the direction and content of writing education by studying the difference in writing ability according to the level of writing knowledge and writing motivation of high school students.
 Methods Using the writing knowledge, writing motivation, and writing ability test tools, 135 general high school students based in Busan were tested. Based on the test results, SPSS 29.0 was used to analyze whether the difference between descriptive statistics and means was statistically significant with gender and grade as variables. In addition, the difference in writing ability according to the level of writing knowledge and writing motivation was analyzed, and differences were analyzed partially by gender and grade, and Cohen's d was calculated.
 Results First, the difference in writing knowledge was statistically significant according to gender, and the difference in writing knowledge and writing ability was statistically significant according to grade. There was no significant difference in writing motivation by gender and grade. Second, as a result of analyzing the difference in writing ability according to the level of writing knowledge and writing motivation, there was also a statistically significant difference in writing ability according to the level of writing knowledge and writing motivation for all students. Third, the difference in writing ability according to the level of writing knowledge and writing motivation by gender and grade was significant in the female student group. There was no difference in writing ability according to the level of writing knowledge and writing motivation for male students. In addition, there was a significant difference in writing ability according to the level of writing knowledge and writing motivation in the second grade, and a significant difference in writing ability according to the level of writing motivation in the third grade was revealed. In the first grade, there was no difference in writing ability according to the level of writing knowledge and writing motivation.
 Conclusions First, writing knowledge differs according to gender and grade, but writing motivation is related to individual students' unique characteristics rather than gender and grade differences, so ways to improve writing motivation should be considered. Second, writing ability can be seen as an improvement due to the natural development of students' growth and the accumulation of writing experiences as the grade goes up, so continuous research on writing education should be conducted. Third, the difference in writing ability according to the level of writing knowledge and writing motivation is significant, and the effect size is also more than medium, so an educational plan for the appropriate input and utilization of writing knowledge and writing motivation is needed to improve writing ability.