There is limited research surrounding non-native speaker-teachers of world languages and the disruption known as the "native speaker fallacy" (Phillipson, 1992), which is the belief that only native speakers can be the most suitable teachers of a given language. This phenomenological study examined the lived experiences of tenured, non-native Spanish-speaking teachers who work across different public high schools on Long Island about their perceptions and experiences of the native speaker fallacy phenomenon. Six in-depth interviews were recorded and coded through the lens of self-efficacy and positioning theories to examine their experiences. The participants showed a strong belief in their teaching capabilities and reported that any insecurities related to their language competency are innate. The participants' limited experiences with the phenomenon led to the realization that their exposure to diversity within their school community is limited. They experienced the most bias enacted by native Spanish-speaker teachers within professional settings outside their workplace. Furthermore, they gauged their self-worth by placing value on many situation-specific factors and subscribing to specific components of professional practice that are influenced by their non-native status. Also, the participants positioned themselves as better suited for teaching non-native Spanish-speaker students. In addition, they developed high emotional self-efficacy from overcoming professional nativeship issues. This study provides opportunities to foster learning and information sharing among native and non-native teachers as a step toward dismantling the divisive nature of harmful societal stereotypes based on the native speaker fallacy. [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.]