The current study investigates whether vocabulary breadth, vocabulary depth, and vocabulary fluency contribute differentially to L2 reading and listening comprehension. One hundred and thirty-eight EFL learners first took three vocabulary knowledge tests that measured vocabulary fluency, vocabulary breadth, and vocabulary depth. Subsequently, they completed the reading and listening components of an IELTS practice test. The structural equation model reveals that vocabulary breadth explained a significant proportion of the variance in both reading and listening scores. Vocabulary fluency demonstrates a significant predictive power over listening comprehension but not reading comprehension. Vocabulary depth has a significant predictive power for listening but not for reading. Pedagogical implications of the results were discussed.