The aim of this study was to examine the gender differences among EFL diploma students in grammar based on an English achievement test. This study was motivated by the observed challenges Saudi students face with mastering grammar, a crucial element of English proficiency that forms the basis of all four aspects of language: listening, speaking, reading, and writing. Despite the same curriculum and evaluation systems in Saudi Arabia's segregated educational context, little is known about possible gender-based disparities in grammar performance. Addressing this gap is important for promoting equitable teaching practices, refining evaluation procedures and optimizing learning outcomes. The study utilized a discrete-point multiple-choice grammar test, as part of an English achievement test, designed to assess students' understanding of grammatical rules taught in their pre-intermediate English course. A total of 237 EFL diploma students (111 males and 126 females) completed the test, and the data were analyzed using an independent sample t-test to investigate differences in grammar performance between genders. The findings indicated no statistically significant differences between males and females, implying that their shared background, textbooks, and assessment standards may lead to comparable performance.