Dual language programs are a form of bilingual education in which emergent bilingual students receive instruction for content and literacy in two languages (Thomas & Collier, 2019). Dual language programs are developed from policies founded on ideologies that are based on instruction for monolingual students, therefore favoring predominantly monolingualism over multilingualism (de Jong et al., 2019; Cummins, 2007; Escamilla et al., 2022; Gort, 2019; Perez Belda, 2021). One of the issues that researchers and educators face is to determine what approaches and services effectively address the specific learning needs of emergent bilingual students (Escamilla et al., 2022). Dual language teachers help emergent bilingual students develop their reading comprehension skills while supporting their advancement with English language proficiency, what is less known is how that support transfers toward biliteracy achievement (Nagle, 2020). This qualitative case study explored dual language teachers' perceptions about effective instructional approaches that help emergent bilingual students develop their biliteracy skills. The study was framed by Vygotsky's (1978) sociocultural theory, Cummins' (1979) linguistic interdependence theory, and Krashen's (1981) theory of second language acquisition. The sample included dual language teachers who held a valid Texas bilingual teacher certification, had at least 3 years teaching experience in the dual language program educational setting, and taught fourth or fifth grade dual language. Data was collected from an online survey, one-on-one interviews, and a focus group. Data collected were coded and emerging themes were identified. The three thematic findings corresponded to each research question: (a) Dual language teachers implement several specific approaches as effective in helping emergent bilingual students reach biliteracy; (b) Dual language teachers perceive the dual language program as a complex system with many components that need to work together for it to be effective and comprehensive; and (c) Dual language teachers monitor and assess student progress to tailor and adjust their instructional approaches based on the unique learning needs of their emergent bilingual students. Findings from this study can be used to develop sound instructional programs that truly meet the academic and linguistic needs of emergent bilinguals and students in dual language programs and influence social change. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]