This dissertation was an investigation of how students in two-way bilingual immersion (TWBI) programs construct their bilingual identities inside and outside the school setting, highlighting the unique and multifaceted nature of their language development and cultural identity formation. TWBI programs aim to cultivate bilingualism and biliteracy, academic achievement, and cross-cultural competencies by integrating students from English-dominant and target language-dominant backgrounds. Using a counternarrative inquiry approach, interviews with seven former TWBI students revealed three main themes: (a) the social value of the bilingual self, (b) self-perception as accomplished learners, and (c) self-perception as cultural agents. The participants, who initially entered TWBI programs from monolingual or bilingual households with English language dominance, achieved high academic success, earning the California Seal of Multilingual Proficiency by the end of high school. Their narratives detail lived experiences that shaped their bilingual identities within and beyond the school context. Student voices, exemplified through their stories, describe social interactions with peers, the influence of teachers, family and home environments, community and social engagement, and the construction of their bilingual identities. These accounts illustrate the rich tapestry of experiences that contribute to the development of a strong, multifaceted bilingual self that permeates all aspects of their lives. [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.]