In this Research Note, we investigate the prevalence and patterns of second-generation Mexican-American children's migration to and return from Mexico during childhood and consider the consequences of this migration for their schooling. Around one in ten second-generation Mexican-American children live in Mexico for some of their childhood. Strong patterns of return to the U.S. through childhood argue for their being considered as part of the Mexican-American second generation even when in Mexico. Their rates of school enrollment in Mexico are much lower than for second-generation Mexican-American children remaining in the U.S. and cannot be explained by their weakly negative selection into emigration. We conclude that country of residence is a far more important determinant of schooling outcome than is migrant status in that country. [ABSTRACT FROM AUTHOR]