The persistent overcrowding of Nigerian correctional facilities underscores a critical weakness in the criminal justice system, particularly the underutilization of non-custodial alternatives. As of 2019, Nigerian prisons housed approximately 49,000 inmates across 234 facilities, with only 20% being convicted offenders and the remaining 80% awaiting trial. This imbalance has created conditions where basic needs such as adequate sleeping space, food, healthcare, and rehabilitative programs are insufficiently met. Furthermore, the lack of infrastructure, trained personnel, and awareness of alternative sentencing options contributes to the continued reliance on custodial sentences, intensifying the overcrowding crisis. The situation is further complicated by inadequate separation of different categories of inmates—juveniles from adults, convicted from awaiting-trial prisoners—resulting in unsafe and unproductive prison environments. This study explores the challenges of prison overcrowding in Nigeria and emphasizes the urgent need to adopt effective non-custodial strategies to improve inmate welfare and promote sustainable rehabilitation