The principle of freedom of contract is the keystone of theprivate law which cannot be waived. There are various modalities andtheories that explains the reasons of protection of consumers. One ofsuch theories which is called “the social model” indicates that theconsumer has to be protected due to its weak nature. This model is not accepted by the prevailing scholars. The opinion that the consumer is the weak part of the contract just because of its nature is not acceptable because this leads to the result that everyone in society is weak since every real person in the society is a consumer. The reason of protection of consumers is based on the idea that the consumers are not able to avail themselves of freedom of contract because of having insufficient information regarding some specific contracts due to the market distortions. This result relies on empirical data derive from research of social fact-events. In such cases that the consumers are not actually able to avail themselves of freedom of contract, intervention of consumer law to the contract is accepted. The intervention to freedom of contract complies with the Constitution as long as it realizes the concrete substantial freedom of contract. The model described as “protection according to circumstances” or “information model” is the prevailing view for today. This model rejects the protection of person who has the sufficient information or competence during the formation of a contract. This model is complemented with “connective model” which provides constitution of specific addresses for defining the concepts of “consumer” and the other part of the contract “seller/supplier” with intent to determine the situations that justify the intervention to the contract and by this way it will not be required to investigate the information and competency of customers each time. Act on the Protection of the Consumer no. 4077 was enacted in 1995 with the intent of harmonization to the European Union legislation. Subsequently some alterations were made and finally new Act on the Protection of the Consumer no. 6502 was enacted in 2014 with the intent of protection of consumers via overcoming the market distortions and in addition to this, it carries the purpose of complete harmonization to the European Union legislation. European Union has been established with the intention of realization of the free movement of goods and services in the common market. In addition to regulations regarding the realization of such intent and providing free competition, it also intends to protect the consumers. In respect of protection of consumers, some of the directives enacted by European Union has the aim of complete harmonization in member states’ legislation and some of the directives are contented with minimum harmonization. Minimum harmonization means that a member state can make regulations for the benefit of customers more than the determined level in a directive of the European Union. However, this right cannot be used against the basic principles of the Union related to common market. In every directive of the European Union, the definitions of “consumer”, “seller/supplier” or “trader” are regulated separately and independently. Besides, it is regulated that which contracts are included in the scope of the directive and which are not. In this system, there is not any principle that protects the consumer in every consumer transaction.