_{The Build–Lease–Transfer (BLT) contract is a form of public–private partnership (PPP) used in implementing major infrastructure projects. In this arrangement, a private company constructs a project with government authorization and, after completion, leases it to the government for a specified period. At the end of the lease term, ownership is transferred to the government. Since the legal nature of such contracts is not clearly defined in Iranian law, their legal framework remains debated. This study aims to clarify the legal nature of the BLT contract and determine its place within the Iranian legal system. The main question is whether it can be classified as a nominate contract under civil law or should be regarded as an independent one. The research uses a descriptive–analytical method and a comparative approach, focusing on similar institutions such as the “lease with ownership condition.” Findings indicate that the BLT contract is governed by Article 10 of the Civil Code. Although it shares similarities with contracts like lease with ownership condition, key differences prevent it from fitting entirely into those frameworks. Given its composite nature combining several nominate contracts toward a single goal it is concluded that the BLT contract is a mixed contract that should be interpreted accordingly.}