This chapter examines the emerging trend of training schools for cybercriminals, commonly known as “yahoo schools,” in Nigeria and their profound implications for national development. As cybercrime becomes a global threat, Nigeria has seen a rise in structured training programs that recruit and educate individuals, particularly youth, in illicit online activities such as hacking, phishing, and money laundering. Drawing on documentary sources, including books, journals, and media reports, the study explores the socioeconomic and technological drivers of this phenomenon, including high unemployment, poverty, weak law enforcement, and the widespread availability of digital tools. It highlights how these schools undermine Nigeria’s economy by deterring foreign investment, eroding digital trust, and fostering a culture that prioritizes quick wealth over ethical standards. The chapter also addresses broader security risks, such as cyberespionage and the involvement of international actors, as well as social issues like ritual killings and the exploitation of minors. Despite government efforts through legislation like the Cybercrime Act of 2015, enforcement challenges, corruption, and societal pressures limit effectiveness. The chapter concludes with recommendations for strengthening legal frameworks, enhancing cybersecurity education, addressing socioeconomic root causes, and fostering international collaboration to mitigate this growing menace and position Nigeria as a leader in the global digital economy.