This study examines the influence of language environment on language and reading skills and the cross-linguistic contributions to reading outcomes in 132 Spanish-English bilingual children ages 7-12 (52% female; 98% Hispanic). We present three major findings: children's language knowledge is separable into general (e.g., phonological awareness) and language-specific (e.g., meaning, grammar) skills; regular Spanish use positively relates to children's Spanish language and reading skills and does not limit English skills; and Spanish reading comprehension is positively associated with English reading comprehension. The model explains a significant percentage of the variance in English (R[superscript 2] = 0.89) and Spanish (R[superscript 2] = 0.87) reading comprehension outcomes. Findings shed light on the interdependence of Spanish and English as they relate to bilingual reading acquisition.