The purpose of this study was to find out the factors affecting the students’ length of study period especially those related to the academic governance, thesis guidance, and supporting facilities at the Faculty of Mathematics and Natural Sciences (FMNS) of the State University of Medan (Unimed) in the academic year of 2017/2018. Questionnaires were distributed to 469 final year students and 170 thesis supervisors (TS), which represented eight study programs and one Bilingual Program, as well as to 32 administration staff (AS) in FMNS of Unimed. Questionnaires consist of 44 (students) or 40 (TS) or 15 (AS) closed and open questions related to administrative and TS services, supporting facilities, and subjects. Data were analyzed descriptively. The results show that the average length of the study period is 8.9 semesters, far longer than the ideal one (8 semesters). The most important factor contributing to the prolongation of the study period is the length of time needed by the students to complete the thesis final project (TFP), which is an average of 1.6 semesters. Factors causing the prolongation of the TFP completion period include: (a) the administrative staff service function is less supportive, (b) supporting facilities (such as SOPs, Thesis Guidebooks, internet, references in libraries, and laboratory facilities) cannot be utilized properly by students, (c) supporting subjects, especially English and Statistics, have not contributed well to the completion of TFP, and (d) the commencement of TFP work, namely in semester VIII, is too late. To overcome the problems, the following actions need to be taken: (a) improving the quality of administrative services and simplifying TFP governance, (b) updating SOPs and thesis guidebooks, library references, internet, and laboratory, (c) increasing the relevance of the contents of supporting thesis courses, and (d) repositioning of TFP courses one semester earlier. Train students early to find and use references to conduct mini-research and student creativity programs, and their involvement in the lecturer’s research will also be very helpful.