This study investigates and classifies grammatical errors with subject-verb agreement in writing made by Saudi students in the foundation year at Taibah University. The students were enrolled in an English language course where they were studying English as a core module. The class was divided into two modules: reading and writing, and listening and speaking. The data was collected throughout the second semester, where students (intermediate-upper intermediate level), were asked to write eight different paragraphs on eight different topics taken from the reading and writing book. The grammatical errors related to subject-verb agreement in writing were identified and classified into three main categories according to their consistency. These errors are mainly categorised as: (a) subject-verb agreement errors with singular subjects (b) subject-verb agreement errors with plural subjects, and (c) subject-verb agreement errors where the main verb or auxiliary verb is compounded with or separated from the subject. The study found that subject-verb agreement errors with singular subjects appear to be more frequent and the most committed among these three categories in students’ writing.

Keywords: Saudi learners, grammatical errors, subject-verb agreement-writing skills.