Although literacy skills have been associated with critical academic, social, and economic outcomes, most adolescents in the United States lack basic proficiency in reading comprehension. Experts in the field of adolescent literacy have identified affective components of reading (e.g., reading attitudes) as a critical topic in need of further research. Prior research has found a significant correlation between affective components of reading and reading comprehension, even after controlling for cognitive covariates (e.g., vocabulary). However, the bulk of this research has been limited to first language learners and children in the early grades. Therefore, this study extends the reading attitudes literature by examining these relationships among Latino adolescents, including those who speak English as a second language. Furthermore, reading attitudes has predicted reading comprehension growth among certain populations, although the mechanisms behind this relationship are unclear. This study theorizes that reading attitudes promotes reading development by facilitating incidental vocabulary acquisition through increased reader engagement and implicit strategy use. Therefore, this study also extends the literature by determining whether reading attitudes predicts vocabulary growth from September to June of ninth grade. Participants were 128 ninth grade students in a low-income, predominantly Latino high school. 24% spoke English only (EO), 26% were from Spanish-speaking homes but had been determined to be initially fluent-English-proficient (I-FEP) at enrollment, 21% were classified as "true" English learners (ELs) who had not yet attained proficiency in English, and 29% were former English learners who had been redesignated fluent-English-proficient (R-FEP). Reading attitudes were assessed using an adapted form of the Elementary Reading Attitudes Survey (ERAS), which contains both recreational (ERAS-R) and academic (ERAS-A) reading subscales. In a hierarchical regression analysis (HRA), the ERAS-R independently predicted reading comprehension after controlling for language group, vocabulary, and word reading ability (i.e., decoding, word recognition, and fluency). No language group interactions were detected. In a second HRA, the ERAS-R predicted students' vocabulary at the end of ninth grade after controlling for language group, prior vocabulary achievement, and word reading ability. However, reading attitudes only predicted vocabulary development for EO and R-FEP students, while no effect was present for I-FEP children and "true" ELs. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]