The high rate of bullying and violence in southern Nigerian schools is a major concern for parents and stakeholders. Bullying is a traumatic health problem that affects individuals, families, and society. Addressing this issue in public secondary schools is urgent because of its lifelong impact. This study served to explore teachers' perceptions and responses to bullying among students in public secondary schools in a school district in southern Nigerian using a multiple case research design. The study was guided with an overarching and subquestions through face-to-face and Zoom interviews. Participants comprised 19 teachers selected via purposeful sampling from three public secondary schools with high bullying rates. The study was grounded in Albert Bandura's social learning theory and Urie Bronfenbrenner's ecological system theory, which explain that children's behavior is influenced by what they have observed and interactions within their environment. Thematic analysis using NVivo 14 software for qualitative analysis was employed to analyze data collected from the open-ended interviews. Findings indicated bullying to be very disruptive to a safe school setting. Also, bullying often stems from family backgrounds, peer pressure, and societal influences. Many students who bully come from neglectful homes or are exposed to negative role models. Peer pressure involves drug use, cult membership, and sexual advances. Teachers often do not respond effectively due to heavy workloads, lack of training, and outdated disciplinary methods. There are no government antibullying laws, and no form of training received by teacher on how to respond to bullying resulting to ineffectiveness in responding to bullying cases. This study provides new insight to this phenomenon, while identifying possible factors responsible for bullying, recommended workable strategies to address bullying in the site studied. [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.]