Abstract Name : Fenny Wiska Student No. : 1409200080044 Study Program : Magister Degree in English Education Department : English Education Title : An Analysis of Cohesive Devices Used in Introduction Sections of Master Theses (A Case Study at Graduate Program in English Education, Universitas Syiah Kuala) Keywords: Cohesive devices, master theses, introduction section, writing quality This qualitative study was employed to find out the use of grammatical and lexical types of cohesive devices in the introduction sections of 20 Master theses of English Education students in Syiah Kuala University along with their influences towards the writing quality. Documentation and checklist were utilized to collect the data obtained from the theses of 2013 to 2017. Then data were analyzed by implementing Halliday & Hasan’s framework (1976) and the modified version the framework of Whitaker (2009). The result revealed that reference became the most frequent grammatical type of cohesive devices appeared 39.36% of the total grammatical types. In addition, in terms of lexical types, reiteration turned to be into the most dominantly used deviced with 48.38% of occurences. The finding also showed that the number of occurences and appropriateness used of cohesive devices used in the students’ thesis introduction sections influenced their writing quality.