The enactment of Senate Bill 100/Public Act 099-0456 (SB100) in 2016 compelled school districts throughout Illinois to evaluate student discipline policies. This dissertation examines the impact SB100 had on middle and high schools throughout the state and within a large suburban K-12 school district. This dissertation is organized into three separate papers. Paper 1 provides a historical context for disciplinary practices used for students in public schools both in Illinois and throughout the country and explores new discipline practices that have emerged since the passing of SB100. Paper 2 examines the implementation of SB100 through an SDT framework to investigate how changing disciplinary practices have impacted school climate and culture. Quantitative data is presented on the number of suspensions and expulsions pre and post 2016. Qualitative data, collected from principal interviews, examines how SB100 has impacted discipline practices, students, and climate and culture is middle schools and high schools. Paper 3 is a presentation any administrator could use for professional development on student discipline practices. The presentation provides background on SB100, a summary of this study, recommendations based on the study, and strategies to meet those recommendations. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]