The influences of word decoding, availability, and accessibility of semantic word knowledge on reading comprehension were investigated for monolingual "("n = 65) and bilingual children ("n" = 70). Despite equal decoding abilities, monolingual children outperformed bilingual children with regard to reading comprehension and availability of semantic word knowledge. Individual differences in reading comprehension were accounted for by differences in availability of semantic word knowledge and to a lesser extent by speed of access to this semantic knowledge. Speed of access accounted for variance in reading comprehension beyond the variance accounted for by decoding and availability of semantic knowledge. A path model suggests that reading comprehension differences between monolinguals and bilinguals are mediated by availability of semantic knowledge. Analyses showed no significant interaction between predictor variables and language background. A multigroup analysis distinguishing proficient and less proficient comprehenders showed a small difference between the two proficiency groups, suggesting that the lexical--semantic variables are more predictive of reading proficiency in the proficient group than in the less proficient group.