The current study endeavours to examine the learning and comprehension patterns of English aspect categories by Yemeni EFL students in the different levels of undergraduate program at the English department, faculty of arts at Sana'a University. The data of the study were collected from a total of 120 students covering the four levels of undergraduate program. From each level, a group of thirty students were considered. The data on aspectual categories were analysed by using statistical models like one-way analysis of variance ANOVA in SPSS 16.0 and Tukey Post Hoc test. The statistical analysis indicates that (1) there is significant differences in the correct uses of the various English aspect categories across the four levels and (2) errors were not equally distributed within all English aspect categories. (3) the use of Tukey Post Hoc test further suggests that performances at specific levels are significantly different from each other. Furthermore, present perfect tense has received the lowest correct answers across all levels, hence it is considered to be the most problematic among the other categories. The role of Arabic influences has been noticed to be negatively affecting the process of learning and comprehension of aspect categories in the initial years, especially in level one students. Some pedagogical implications have been given.