The purpose of this paper is to analyze the writing motivation level and gender differences on writing performance in middle school students. To this end, the survey of writing motivation and writing performance have been carried out with 435 students in DeaJeon, Gyonggi, and Jeonra, and then the collected data have been analyzed. There was a statistically significant difference between the students who have a high writing motivation and the students who have a low writing motivation on writing performance score. In addition, the difference in sub-factor's score―content, organization, expression and usage was statistically significant. This result is enough to show that writing motivation have a important effect on writing performance. Also, female's mean score was higher than the male's in middle school students' writing performance. And there were statistically significant difference in these groups. In all sub-factors, not organization, female got higher mean scores than male did, the difference was statistically significant. In case of female, writing performance score show little improvement in higher grades. In case of male, writing performance score is lower in middle school 3 grade. The conclusion means that it should be considered of writing motivation and gender difference for more successful writing performance in writing education.