A structural equation model of second language (L2; English) reading comprehension was tested on a sample of 135 Spanish-speaking 4th-grade English-language learners (ELLs). The model included 2 levels: decoding and oral language. English decoding measures included alphabetic knowledge and fluency. English oral language measures included vocabulary knowledge and listening comprehension. The model had reasonable goodness of fit. Decoding skills played a less predictive role than oral language proficiency. L2 listening comprehension made an independent, proximal contribution to L2 reading comprehension, whereas L2 vocabulary knowledge assumed both proximal and distal relationships with L2 reading comprehension. Results suggest that, given adequate L2 decoding ability, L2 vocabulary knowledge is crucial for improved English reading comprehension outcomes for Spanish-speaking ELLs.