Abstract : This thesis discusses (the principle of the opposability of contract), which regulates the outer frame of the contract. The "principle of the binding force of contract" regulates the subject of the contract in terms of the effects of binding contractual obligations, whereas the "principle of specificity of contract effect" regulates the personal scope of these effects. Accordingly, the principle of the opposability of contract is a complement to both principles, so that it regulates - in the face of others the contract's effects that have material character different from the binding contractual effects which are imposed on contractors, in principle. Therefore, the study of the principle of the opposability of contract addresses the existing fact of the contract for others without that other person should be a creditor or debtor under such contract As the French jurisprudence has practiced opposability long time ago and adopted by the judiciary, it remains for the scholars of the Arab an ambiguous principle. The thesis is based on the methodology of comparative research, focusing on the Bahraini law with reference to French and Egyptian laws, as well as to the position of the judiciary and jurisprudence in France and Egypt, in addition to the provisions of the Court of Cassation in Bahrain. The thesis is divided into three chapters. Chapter I, discusses inveterating the principle of the opposability of contract, by reviewing the historical and intellectual circumstances over which the principle has passed amid the traditional concepts of the legal prevailing principles, leading to the development of these principles and emergence of the need for the principle of opposability, then reviewing attempts of jurisprudence to establish the principle of opposability and the criticisms directed against it, and ending by clarifying the scope of this principle and its limits. The second chapter deals with the principle of the opposability of contract in the face of others, which reviews the traditional concept of the principle of opposability by the nature of the contractual effects. It talkes about the contracts that produce real effects, the extent to which the opposability of real estate contracts relates to registration or record, the extent to which the opposability of contracts on movables relates to possession, the opposability of contracts producing the personal effects, through the statement of the opposability of these contracts in general as they acquire opposability once concluded for they relate to the financial assets of the debtor, and then, indicating the situations established by the legislature to strip these contracts of its opposability, whether on the basis of all the actions of the debtor or some of them. This chapter ends with the statement of the development of the concept of this principle, when third- party liability for breach of contract appear, through the jurisprudential attempts to establish such liability, and statement of the privacy of such liability in terms of the elements,conditions its existance, and its compensation system. Chapter III touches upon the principle of the opposability of contract in the face of the contractors, It deals with the idea of protest by non-contractors in the face of contractors under the principle of the opposability of contract as to explain the basis of the responsibility of the contractor to third parties for the breach of the contract (or the poor implementation of the contract) and its elements judicial precedents that have been made in this regard, the nature of this responsibility, and the negative aspects of its optimal application when so interconnected contracts are underway where the responsible party and the injured party on the status of contracting while there is no contract between them, as well as the solutuion by jurisprudence to address that. A review, then, will be to disscuss the principle of the opposability of contract within the frame of the group of contracts, through the statement of the nature of theory and resulting effects that deal with the principle of specifity and the principle of opposability, criticism made against such theory in reation of its basis and consequences. And then we touch upon the position of the judiciary towards the application of this theory, as for the group of contracts involving the transfer of ownership, as well as the one not involving =-ownership transfer. At the end of this thesis, we list the most important findings concluded from the study of the principle of the opposability of contract, followed by a series of recommendations related to the Bahraini civil law by proposing amendments.