Jungle justice, also known as mob justice, refers to the extrajudicial punishment of individuals suspected of crimes, often through public lynching or killings without lawful trial. In Nigeria, this practice has become a persistent plague within the justice system, reflecting both the failure of law enforcement agencies and the erosion of public trust in formal legal institutions. It violates fundamental rights enshrined in the Constitution of the Federal Republic of Nigeria, 1999, including the rights to life, fair hearing, and the dignity of the human person. Jungle justice also poses a significant threat to the rule of law. This article examines the root causes and implications of jungle justice and argues that it directly undermines the rule of law and the protection of fundamental rights in Nigeria. It concludes with practical recommendations for institutional reform, enhanced public education, and strengthened mechanisms for upholding fundamental rights.