Data from a unique new survey of over 1,000 teachers in K-12 public schools across the country show that our teaching force is largely segregated. Using this new dataset, I find that teachers of different races are teaching students of very different racial composition, adding an extra dimension to growing student racial segregation. White teachers comprise an overwhelming majority of the nation's teachers. Yet at the same time, they were the least likely to have had much experience with racial diversity and remain remarkably isolated. The typical African American teacher teaches in a school were nearly three-fifths of students are from low-income families while the average white teacher has only 35% of low-income students. Latino and Asian teachers are in schools that educate more than twice the proportion of English language learners as schools of white teachers. Nonwhite teachers and teachers who teach in schools with high percentages of minority or poor students are more likely to report that they are contemplating switching schools or careers. The article concludes with recommendations for diversifying the teaching force and ensuring that schools serving students of all backgrounds have a racially integrated, highly qualified faculty. (Contains 30 tables and 32 footnotes.)