Background: Vocabulary knowledge (VK) and morphological awareness (MA) are crucial linguistic variables for reading comprehension. However, the extent to which MA subskills are intertwined with different facets of VK in their contributions to reading comprehensions, and how MA influences the reading abilities of English as a foreign language (EFL) readers, remains largely underspecified. The main purpose of the current study was to examine the relative significance of VK and MA in foreign language reading ability and to identify the direct and indirect pathways from various facets of MA to EFL reading comprehension. Methods: A total of 396 EFL learners took a standardised reading test (TOEIC), along with a battery of three MA tests and two VK tests, which assessed both the breadth and depth of VK. Results: (1) Hierarchical regression analysis indicated that both VK and MA had significant effects on EFL reading comprehension, with VK contributing more to reading comprehension than MA. (2) Path analysis showed that MA had both direct and indirect effects on EFL reading comprehension via the breadth and depth of VK. Conclusions: Our results established that VK was a stronger predictor of reading comprehension than MA and elucidated the direct and indirect pathways within the morphological pathways framework through which MA contributes to reading comprehension. Relevant implications were discussed based on the results.