Second-generation Latinx immigrant students in middle school and high school may experience language and reading barriers in education resulting from their cultural upbringing. This study examined the language and reading scores of 2,107 bilingual dominant second-generation Latinx youth participants enrolled in 8th and 9th grade in the states of California and Florida. Results showed that bilingual dominance in English and Spanish is positively related to reading achievement scores, even when controlling for demographic variables. This study also found evidence that family cohesion and self-esteem mediated the relationship between bilingual dominance and reading achievement scores. This study provides insight into future research on the reading achievement of second-generation Latinx immigrant students. Implications for school administrators and educators regarding reading and language achievement for second-generation immigrant students will be shared with recommendations.