School discipline referrals (SDRs) may be useful in the early detection and monitoring of disruptive behavior problems to inform prevention efforts in the school setting, yet little is known about the nature and validity of SDRs in the early grades. For this descriptive study, SDR data were collected on a sample of first grade students who were at risk for developing disruptive behavior problems (n = 186) and a universal sample (n = 531) from 20 schools. Most SDRs were given for physical aggression and the predominant consequence was time out. As expected, boys and at-risk students were more likely to receive an SDR and to have more SDRs than were girls and the universal sample. A large difference between schools regarding the delivery of SDRs was found. A zero-inflated Poisson model clustered by school tested the prediction of school-level variables. Students in schools that had a systematic way of tracking SDRs were more likely to receive one. Also, schools with more low-income students and larger class sizes gave fewer SDRs. SDRs predicted teacher ratings, and to a lesser extent, parent ratings of disruptive behavior at the end of first grade. Practitioners and researchers must examine school-level influences whenever first grade discipline referrals are used to measure problem behavior for the purpose of planning and evaluating interventions. © 2007 Wiley Periodicals, Inc. Psychol Schs 44: 333–350, 2007.