Abstract :
The aim of this research was to find out students? skill in writing the thesis conclusion
grammatically. The indicators were : (a) Errors in tense, (b) Errors in Preposition, (c) Errors in
Punctuation. From these indicators, the researcher find out students? skill in making conclusion
of their thesis grammatically. This research was qualitative descriptive research. The population
was the students that had graduated on 2015-2017 of University of Pasir Pengaraian. Sample of
this research were 75 thesis conclusions of 75 students. The conclusion of this research showed
each of students made errors in all of indicators and the most errors was in tense. The errors
caused by Interlingual Transfer, Overgeneralization, Carelessness, and Communication
strategy.