This qualitative descriptive phenomenological study explored the adaptation experiences of 11 foreign-born adults who are teaching in the Southeastern United States P-12 public schools. Gordon's theory of assimilation guided the research, which asserted that assimilation is the progression of inclusion by which strangers become complete participants of an alternative group or culture. The study added to the literature on assimilation by exploring the lived experiences of a select sample of foreign-born individuals from Asia, Jamaica, Africa, India, Europe, and Latin America who migrated to the United States as adults. Two research questions that guided the study include (1) How do foreign-born adults adapt to teaching in public schools in the United States? (2) How have the lived experiences of foreign-born teachers influenced their adaptation in U.S. public schools? Data analysis was guided by Giorgi's five steps to qualitative data analysis. Themes derived from data evidenced Gordon's theory of assimilation by lived experiences. The ideas include adapting to culturally diverse work environments, certification to qualify, language barriers, lack of teacher respect, and immigrants' relevance in the workplace. The paradigm of the theoretical foundation generated ten themes to include: RQ1: (a) certification, (b) preparation to teach, (c) organizational and teacher similarities, (d) teacher involvement in ensuring student success, (e) nature of the relationship with other teachers and administrators, and (f) support system. RQ2: (a) distinctions, (b) challenges, (d) pursuing the American dream, and (e) the relevance of a foreign-born teacher. [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://www.proquest.com/en-US/products/dissertations/individuals.shtml.]