One of the most striking features of crime in America is its disproportionate concentration in disadvantaged, racially segregated communities. In this paper we estimate the effects of court-ordered school desegregation on crime by exploiting plausibly random variation in the timing of when these orders go into effect across the set of large urban school districts ever subject to such orders. For black youth, we find that homicide victimization declines by around 25 percent when court orders are implemented and homicide arrests also decline significantly, which seem to be due at least in part to increased schooling attainment. We also find positive spillover effects to other groups, with beneficial changes in homicide involvement for black adults and perhaps whites as well. Our estimates imply that imposition of these court orders in the nation's largest school districts lowered the homicide rate to black teens and young adults nationwide by around 13 percent, and might account for around one-quarter of the convergence in black-white homicide rates over the period from 1970 to 1980. Four appendices are included: (1) A brief history of school desegregation decisions; (2) Data; (3) Additional estimation details; and (4) Bordering county group analysis.