The COVID-19 pandemic extensively changed the work life of many employees. Teachers seemed particularly challenged, confronted with sudden remote teaching due to school closures. Drawing on the job demands-resources (JD-R) model, we investigated (a) changes in seven work characteristics (job demands: emotional demands, interpersonal conflict, workload; job resources: autonomy, social support, feedback, task variety) and three job-related well-being indicators (fatigue, psychosomatic complaints, job satisfaction), (b) how changes in work characteristics correlated with well-being, and (c) the impact of two individual difference factors (caretaking responsibilities, career stage). Data were collected in two waves (just prior to and a few months into the COVID-19 pandemic) across Germany from 207 teachers with an average work experience of 6 years (range: 1-36 years). Using latent change score (LCS) modeling, we found significant, small-to-medium-sized decreases over time for both job demands and resources as well as fatigue, with variability in the magnitude of changes. Decreases in job demands correlated with decreases in fatigue and psychosomatic complaints, whereas decreases in job resources correlated with decreases in job satisfaction. Teachers with caretaking responsibilities and more experienced teachers were more vulnerable to the crisis as they experienced a smaller or no decrease in job demands in concert with diminished job resources. These findings reveal the double-edged consequences of the COVID-19 pandemic for teachers' work life.