There have been a lot of research studies on the role of motivation in education and language learning. However, research on the role of motivation in the area of EFL (English as a foreign language) writing is a rare undertaking. This study aimed to examine the correlation between EFL students' motivation in writing and their writing proficiency. It also compared female and male students in terms of their motivation in writing and their writing proficiency. This study involved 55 university students of English department (17 female and 38 male students) who were required to write essays and respond to a motivation in writing questionnaire. The results showed that there was a high correlation between the EFL students' motivation in writing and their writing proficiency. It was also revealed that there were significant differences in the motivation in writing as well as writing proficiency of the female and male students. The findings of this study suggested that the EFL students who had a higher level of motivation in writing had better writing proficiency. The study also showed that female students outperformed male students in terms of both motivation in writing and writing proficiency.