This paper examines teachers’ mobility in response to exogenous changes in the credentials of their students using data from Stockholm high schools. I explore a major admission reform that lead to the reshuffling of students between schools within the municipality of Stockholm. The results show that a 10-percentile-point increase in student quality decreases the probability of a separation by up to 9 percentage points. These effects are very similar across all types of teachers and are found mainly for mobility between schools rather than out of the profession. They are also present only in the lower half of the student quality distribution. Teachers react mostly to direct measures of student quality (grades from compulsory school) rather than to other characteristics that are correlated with student quality (immigrant status, parental income, paternal cognitive skills). Finally, I do not find any significant effects of changes in student quality on individual teacher’s earnings or school hiring policies.