This study aims to analyze the grammatical errors made by senior high school students at SMAN 1 Padang Tiji in writing recount texts. Recognizing the significant role of grammar in writing proficiency and its critical importance in English language acquisition, this research investigates the types of grammatical errors commonly made by students and identifies their underlying sources. Utilizing a mixed-method approach, the study involved document analysis of students' written recount texts, with data collected from ten students selected through purposive sampling. The findings reveal five primary types of grammatical errors: verb errors, conjunction errors, article errors, preposition errors, and pronoun errors, with verb errors being the most frequent. The study further classifies the sources of these errors into three categories: intralingual errors, interference errors, and developmental errors, with intralingual errors being the most prevalent. This research contributes to a deeper understanding of the grammatical challenges faced by EFL learners and provides practical insights for educators to develop targeted instructional strategies that enhance students' grammar proficiency in writing recount texts.