Principles of Unjust Enrichment in Nigerian Law: Emerging Trends in Restitutionary Claims

The doctrine of unjust enrichment, which obligates a party to make restitution when they have been enriched at another's expense in circumstances the law regards as unjust, is gradually emerging as a recognised area of Nigerian private law following decades of judicial uncertainty. This study examines emerging trends in restitutionary claims based on unjust enrichment in Nigerian courts, analysing decisions from the Supreme Court, Court of Appeal, and commercial divisions of state High Courts from 2018 to 2024. Using a doctrinal methodology, the research maps the conditions under which Nigerian courts have granted restitutionary relief, focusing on cases involving mistaken payments, failed contracts, and proprietary restitution in commercial disputes. The study draws extensively on developments in English, Australian, and Canadian unjust enrichment jurisprudence to assess whether Nigerian courts are moving toward a principled law of unjust enrichment or continuing to rely on outdated implied contract fictions. Primary data from interviews with 20 commercial litigators in Lagos and Abuja provides insight into how restitutionary claims are pleaded and received in practice. Findings suggest a gradual judicial acknowledgment of unjust enrichment as a standalone cause of action, though significant doctrinal gaps remain. Recommendations include academic engagement, judicial education, and legislative codification of restitutionary remedies. Keywords: unjust enrichment, restitution, Nigerian private law, mistaken payment, restitutionary claims