The present study examined the relationships between English reading comprehension and its component constructs-phonological processing, semantic knowledge, syntactic processing, and reading rates-among university learners. A total of 54 university students who had taken TOEIC were recmited from a private university in northern Taiwan. With regard to the components, phonological processing was measured by phonological awareness and rapid digit naming, semantic knowledge by a vocabulary size test, and syntactic processing by an online grammaticality task where accuracy and reading rates were simultaneously recorded. Pearson's correlations show that all the experimental measures were correlated moderately to highly with their TOEIC reading scores, suggesting a positive pattern that the higher the participants' reading comprehension scores , the better their performance on the reading-related measures. But both speeds of rapid digit naming and syntactic processing were negatively correlated with reading comprehension, indicating that the better their reading comprehension, the shorter they spent on digit naming and sentence reading. Furthermore, regression analyses indicate that vocabulary was the strongest predictor of the adult learners' reading comprehension and that syntactic knowledge came in second. Surprisingly, phonological awareness was the third valid predictor of these EFL adult learners' reading comprehension. The findings altogether suggest that vocabulary and syntactic knowledge are two aspects that should be emphasized and that phonological awareness is another aspect that should not be neglected for reading success in English at the tertiary level.