Exclusionary discipline -- suspensions or expulsions that remove students from the learning environment -- can have long-lasting, negative impacts on a student's trajectory. Research suggests that students who are suspended or expelled suffer academically and are more likely to drop out and be involved in the criminal justice system later in life. Yet in 2015-16, about 2.7 million students in K-12 received one or more out-of-school suspensions, and over 120,000 students were expelled with or without educational services. These data -- coupled with research showing significant disparities in the application of suspension and expulsion based on race, gender and disability status -- have prompted many state education leaders to re-examine their school discipline practices. This Policy Analysis highlights research on school discipline, past state policy trends, current policy examples and considerations for policymakers examining their state's policies. It also looks at how states address school discipline data in their plans under the Every Student Succeeds Act.