A significant proportion of migrant children in China are not able to attend public schools for lack of local household registration (HuKou), and turn to privately-operated migrant schools. This paper examines the consequences of such a partially involuntary school choice, using survey data and standardized test scores from field work conducted in Shanghai. We find that migrant students who are unable to enroll in public schools perform significantly worse than their more fortunate counterparts in both Chinese and Mathematics. We also use parental satisfaction and parental assessment of school quality as alternative measures of the educational outcome and find similar results. Our study suggests that access to public schools is the key factor determining the quality of education that migrant children receive.