The aim of this research is to analyze the grammatical errors in writing a thesis proposal. The researcher conducted study because a lot of errors in writing a thesis proposal still made by a student. The research type is descriptive qualitative. Qualitative descriptive‟ is a viable and acceptable label for a qualitative research design. Therefore, this research described the observed phenomena in the form of words. The population of the study was all students of the class b, the eighth semester of TBI at UIN Mataram. With relation to sample in this study, purposive sampling technique was used to take the sample. So, in the interest of the sample, the researcher took one student for analyzing her thesis proposal, as the objects based on the types of grammatical errors namely Subject-Verb Agreement Error, Verb Form Error, Verb Tense Error, Singular/Plural Error and Word Form Error. Based on the data analyzed, it was found that the frequent and dominant errors done by a thesis proposal of a student are as follow: Subject-Verb Agreement (17,85%), Verb Form (35,71%), Verb Tense (10,71%), Singular/Plural Noun Form (10,71%), and Word Form (25%). Whereas, the dominant error is Errors related to Verb Form that comprises 10 errors (35,71%).
Keywords: Grammar, a thesis proposal, errors analysis
