It is well established that monolingual preschoolers' oral language development (vocabulary and oral comprehension) contributes to their later reading abilities; however, less is known about this relationship in bilingual populations where children are developing knowledge of two languages. It may be that children's abilities in one language do not contribute to their reading abilities in their other language or that children's experiences with either language assist them in developing a common underlying proficiency that they draw upon when learning to read. The purpose of this study was to investigate the relationship among bilingual children's receptive language development and reading outcomes in first grade. Eighty-one bilingual children who were attending Head Start participated in the study. Growth curve models were used to examine the relationship between children's language abilities during two years in Head Start and reading outcomes at the end of first grade. Children's growth in both English and Spanish receptive vocabulary and oral comprehension predicted their English and Spanish reading abilities at the end of first grade within languages. Associations were also observed between languages with growth in English receptive language predicting Spanish reading comprehension and growth in Spanish receptive language predicting English reading comprehension. Learning outcomes: The reader will be able to (1) describe the common underlying proficiency model; (2) identify key factors of consideration when studying bilingual children; (3) understand the associations between preschool language abilities in English and Spanish and English and Spanish reading outcomes; and (4) identify ways in which future clinical practice may be impacted by the study's findings. (author abstract)