This article critically examines the concept, legal foundation, and practical implementation of non-custodial sentencing in Nigeria, with particular focus on the Administration of Criminal Justice Act (ACJA) 2015 and its complementary framework under the Nigerian Correctional Service Act 2019. It interrogates the extent to which these legislative reforms have transformed Nigeria’s traditionally incarceration-driven penal system and evaluates their effectiveness in addressing chronic prison congestion, prolonged pre-trial detention, and systemic inefficiencies within the criminal justice process. The study traces the historical development of non-custodial measures in Nigeria, highlighting earlier statutory provisions that permitted alternatives to imprisonment, and situates the ACJA reforms within broader global trends that increasingly prioritize rehabilitation over retribution. Through doctrinal analysis of statutory provisions, judicial decisions, and scholarly commentary, the article assesses key non-custodial measures such as probation, suspended sentences, community service, and parole. It further identifies institutional, structural, and attitudinal challenges that hinder effective implementation, including judicial conservatism, inadequate monitoring mechanisms, limited awareness among stakeholders, insufficient funding, and weak inter-agency coordination. The paper argues that while the statutory framework is progressive and aligned with modern penal philosophy, its transformative potential remains constrained by practical enforcement gaps. Ultimately, the article contends that properly implemented non-custodial sentencing offers a viable pathway for reducing prison overcrowding, safeguarding constitutional rights, minimizing recidivism, conserving public resources, and fostering restorative justice. It concludes that strengthening institutional capacity, enhancing judicial training, improving data-driven evaluation, and expanding public awareness are essential steps toward realizing the full rehabilitative and reformative objectives of Nigeria’s criminal justice reforms.