This study aims to examine several writing errors or mistakes found in academic works by students in the process of completing their final assignments. The method used in this research involved analysing samples of students’ theses through the lens of standard writing language criteria. The findings of this study reveal the following: 1) Errors in the use of capital letters occurred 48 times (30.20%). 2) Errors in the usage of prepositions di, ke, and dari, as well as the prefixes di- and ke-, occurred 13 times (8.17%), comprising 10 errors in prepositions and 3 errors in prefixes. 3) Errors in punctuation usage occurred 68 times (42.76%), including 12 errors in using periods (.), 22 errors in commas (,), 18 errors in hyphens (-), 3 errors in question marks (?), and 13 errors in colons (:). This study contributes to understanding common writing errors in academic works by highlighting the frequency and types of errors related to capitalization, prepositions, prefixes, and punctuation. The findings provide insights that can help educators design targeted interventions to improve students' academic writing quality.