ABSTRACT Nurul Fajri, 2015. Assessing Unity, Coherence and Word Usage in Students’ Writing (A descriptive Study at English Department of Tarbiyah Faculty of IAIN Ar-Raniry). Thesis, Study Program: English Language Education, Graduate Program, Syiah Kuala University. Advisors: (I) Prof. Dr. Bahrein T. Sugihen, M.A. (Emeritus) and (II) Dr. Sofyan A.Gani, M.A Key Words: Writing, Unity, Coherence, and Word Usage This research is done to find out whether students use the unity, coherence, and word usage appropriately in their paragraph and the most errors made by students toward unity, coherence and word usage in constructing their paragraph. This is qualitative research, where all the data are described in a systematic way based on the proposed research questions. The subject for this research was the second year students of English Department of Tarbiyah Faculty of IAIN Ar-Raniry that consisted of 21 students. To obtain the data, the writer asked the students to write about themselves on the topic about their autobiography and physical appearance. As a result of this research, some of the students did not use the unity, coherence, and word usages appropriately in their paragraph, and the most errors made by the students in constructing their paragraph is in using word usage. It could be proven from the students’ writing test that there is 137 errors (79,19%) from the total numbers of the students did errors regarding word usage. It was found that students make errors regarding spelling improvement, and omitted words and letter. Nevertheless, the errors of unity are 30 errors (17,04%), and 9 errors (5,11%) of coherence. Moreover, it was also found that the errors made by the students were influenced by the mother tongue, and were also caused by the difficulties of the students in learning the second language. Because of that, it could be concluded that many of the students made errors because of interlingual and intralingual transfer. Hence, it could be said that the students’ writing generally was not constructed by using unity, coherence, and word usage.