This study investigates the relationships among working memory (WM), syntactic parsing ability (SP), and L2 reading performance across varying proficiency levels. A cohort of 120 L1-Persian EFL learners was categorized into beginner, intermediate, and advanced proficiency groups based on their IELTS scores. Participants completed a reading span test, a sentence segmentation task, and a reading test to measure WM, SP, and L2 reading ability, respectively. Statistical analysis revealed significant differences in syntactic parsing and reading abilities across proficiency levels, with advanced learners outperforming their intermediate and beginner counterparts. Moreover, significant relationships were identified between WM, SP, and L2 reading performance among participants in the beginner group, while such relationships were not observed in the intermediate and advanced groups. Additionally, the results identified SP as a robust predictor of L2 reading performance, specifically within the beginner proficiency level, suggesting that syntactic parsing abilities substantially contribute to variations in L2 reading outcomes at this proficiency level. Focusing on the intricate interplay between cognitive resources and reading processes, these findings underscore the essential role of syntactic parsing in enhancing L2 reading comprehension among beginner learners, highlighting the necessity for targeted instructional strategies to support the development of these skills.