The study aimed to analyze the common grammatical errors of students in academic writing. Mixed-method research was implemented for this study. The study team gathered 110 essays from learners in the Writing Course 4 – Social Texts classroom. Then, the researchers conducted interviews with 23 learners in order to ascertain the reasons behind their grammatical errors in writing and provide suitable remedies. Participants in this research were second-year students majoring in English Studies in the Department of English Language and Culture's High-Quality Program at a Vietnamese university. The findings revealed that the errors that made up the biggest percentage of all errors were those involving the articles (25,5 %), prepositions (14,2%), and plural/singular forms (13,7 %). On the other hand, tenses (7%), passive voice (3,8%), and subject-verb agreement (1,7%) errors had the respective lowest percentages. The results of the interviews with 23 randomly selected students in this course showed that students struggled with academic writing on a number of different levels, with the root causes being a lack of vocabulary knowledge, carelessness, and uncertainty about basic grammatical structure.<p> </p><p><strong> Article visualizations:</strong></p><p><img src="/-counters-/edu_01/0124/a.php" alt="Hit counter" /></p>