In 2021, Nigeria had an estimated 1.9 million people living with the human immunodeficiency virus (PLHIV) and 1.7 million (90%) on antiretroviral therapy (ART). Study Design: A systematic review and meta-analysis. This meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) 2020 guidelines. We searched PubMed, Embase, PsychINFO, CINAHL, Global Index Medicus, and Cochrane Library. Studies were included if they reported on ART retention in care among PLHIV in Nigeria. The random-effects meta-analyses were used to combine the studies that had complete retention data. The I2 statistic was used to assess the heterogeneity of the studies. A sensitivity analysis was then done by conducting a leave-one-out analysis. Afterward, data were analyzed using STATA version 18. The search yielded 966 unique articles, of which 52 studies met the inclusion criteria for the meta-analysis, and four experimental studies were split into their component arms. The total number of study participants was 563,410, and the pooled retention rate was 72% (95% CI: 67%, 76%; I2=99.9%; n=57). Sub-analysis showed that the Southeast region of Nigeria had the highest retention of 86% (95% CI: 78%, 92%), and the South-South had the lowest retention (58%; 95% CI: 38%, 79%). In Nigeria, the pooled ART retention rate is less than optimal to achieve the UNAIDS goal of 95%, thus developing new models for ART retention is needed.