Teacher attrition, or teachers voluntarily leaving the field, has been a persistent problem in United States public schools and serves as one of the primary drivers of the urgent teacher shortage crisis. Mitigating teacher attrition requires a comprehensive and nuanced understanding of why teachers leave the field. This dissertation employs three distinct yet interconnected studies examining the factors which contribute to teacher attrition to contribute to such an understanding. The studies are related sequentially and thematically, beginning with the first study, a scoping historical review of the literature on teacher-reported reasons for leaving the field, considering what the factors are and how they have changed over time. Informed by the findings of the review, the second study employs a Netnography of "Why I Quit Teaching" YouTube videos to analyze former-teacher vloggers' given reasons for leaving their classrooms, complementing the historical perspectives from the first study with contemporary ones. Finally, the third study further narrows the scope to examine how educational intimidation policies and the politicization of curriculum and identity in schools contribute to teachers' decisions to leave the field. The analyses affirm well-known and longstanding factors contributing to teacher attrition (e.g., administrative support, salary), and provide insight into more contemporary issues, such as violence and political tension, which impact teachers' contemporary leaving decisions. Implications for research and policymaking are discussed. [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.]