Despite growing concern over teachers' ability to live comfortably where they work, we know little about the systematic relationship between affordability and teachers' well-being, particularly in high-cost urban areas. We use novel survey data from San Francisco Unified School District to identify the patterns and prevalence of economic anxiety among teachers and assess how this anxiety predicts teachers' attitudes, behaviors, and turnover. We find that San Francisco teachers have far higher levels of economic anxiety on average than a national sample of employed adults, and that younger teachers are particularly financially anxious. Furthermore, such anxiety predicts measures of job performance and teacher retention--economically anxious teachers tend to have more negative attitudes about their jobs, have worse attendance, and are 50% more likely to depart the district within 2 years after the survey.