A majority of Latino adolescents are reading below a proficient level, according to federal data, and there is a significant gap between overall reading proficiency of Latino and non-Latino, Caucasian adolescents. The purpose of this study was to investigate the linguistic underpinnings of Latino students' text comprehension. A positive relationship appears to exist between idiom comprehension and academic achievement, as well as idiom comprehension and reading comprehension, in typically developing, monolingual adolescents. Since reading comprehension and idiom comprehension share many of the same linguistic processes, idiom comprehension may provide a unique perspective for investigating Latino adolescents' reading comprehension. Using the Global Elaboration Model (GEM, Levorato, Nesi, & Cacciari, 2004) as the conceptual framework, the present study examined the relationship between idiom comprehension and reading comprehension with a population that had not been studied in this manner: bilingual (Spanish-English) adolescents in West Central Florida and their monolingual (English-only) peers. The GEM posits that idiom comprehension develops in tandem with other linguistic development requiring inferencing ability; and that idiom x comprehension ability can be predicted by reading comprehension ability. The present research design included the evaluation of idiomatic familiarity, semantic transparency, and contextual support, as well as three other linguistic measures: a) a reading comprehension task, b) an error detection task, and c) a synonym task. Results indicated that the three linguistic measures predicted 33% of the variance in idiom comprehension accuracy; and error detection was the strongest predictor of idiom comprehension accuracy. Furthermore, monolinguals outperformed bilinguals on all measures. The synonym task, a measure of lexical depth, best predicted language group membership. There was a three-way interaction among idiomatic familiarity, semantic transparency, and contextual support; and a three-way interaction among familiarity, transparency, and language group. Lastly, the three linguistic measures significantly predicted the bilinguals' amount of English experience, with qualitative differences emerging between sequential and simultaneous language learners. Findings lend support to the psychological reality of the GEM and provide insight into the linguistic foundations of reading comprehension in Spanish-English bilinguals.