Turkish Law has adopted the renowned principle of pacta sunt servanda. Therefore, the former Code of Obligations numbered 818 did not provide a general provision for neither the adaptation of the contract and nor the termination of the contract in case of hardship. Even then, the Court of Cassation and legal scholars accepted adaptation of contracts in the occurrence of the unexpected event, such as economic crises. The new Turkish Code of Obligations numbered 6098 which came into effect as of 1 July 2012 has introduced a general clause for adaption of the contract. Accordingly, the obligor may demand the adaptation or the revocation of the contract if adaptation is not possible through meeting all of the required conditions. This chapter presents an overview of the conditions and the consequences of adaptation of the contract under Turkish Law and specifically analyzes the option for renegotiation of the contract in comparison to the UNIDROIT Principles (6.2.3), Principles of European Contract Law (PECL 6:111) and Draft Common Frame of Reference (DCFR III.-1:110).