Abstract: The article is devoted to the study of the problem of identification of a weak party of the contractual relationship. The author deals with the weak party of the contractual relationship through the perspective of the interdisciplinary principle of defense of a weak party. The author analyzes the foreign regulations, including the German and French ones. The article analyzes the regulations of the current legislation of the Russian Federation, juridical literature, and judicial practice. Various approaches are given regarding the determination of signs of a weak party of the contract. The article deals with the possibility of acknowledging the subject of entrepreneurial activity as a weak party of the contract. The author applies the general scientific and special juridical methods. The general scientific methods include the comparison, as well as the method of rising from the abstract to the concrete. The special juridical methods include technical and dogmatic methods. One can view the concept of a weak subject in the contractual relationship through the perspective of the interdisciplinary principle of defense of a weak party. The author suggests that both the subject of entrepreneurial activity and the government can serve as a weak party of the contract in the contractual relationship. The conclusion is drawn that there is no framed approach in determining the weak party of the contract. There is a need for further development of this concept and its criteria.