The word "advertising" originates from the Latin word "clamere," which means "to call out." In our legislation, advertising is defined in the Advertising Directive. According to Article 2 of the AD, advertising is defined as "an activity carried out with the aim of promoting the supply of products or services, including real estate, rights, and obligations." It should be noted that the definition of advertising is not only found in the Advertising Regulation. However, it is necessary to mention that the definition in the Advertising Regulation is quite explanatory.

In essence, comparative advertising forms a type of advertising. Here, the owner of a product or service not only praises their own product or service but also compares it to a competitor's product or service. Therefore, two elements are necessary for advertising to be considered comparative advertising. First, there must be a comparison, and additionally, there must be an association.

Comparison can be explained as the juxtaposition of two products or services that serve the same function in a way that the outcome can be demonstrated. It is important to underline that the outcome must be demonstrable. Therefore, simply telling the consumer to make a comparison does not turn the advertisement into comparative advertising. On the other hand, if it can be concluded from the characteristics of the situation that a comparison has been made, then the advertisement is considered comparative advertising.

Comparative advertising can be done directly or indirectly as mentioned above. Furthermore, comparative advertising can be classified as positive or negative based on its content. In positive comparative advertising, the advertiser claims their product or service is better than that of a competitor. Conversely, in negative comparative advertising, the advertiser points out the disadvantages of the competitor's product or service compared to their own.

Comparative advertising can involve association in different forms. Firstly, comparative advertising can be critical. Here, the advertiser highlights their product or service by criticizing those of competitors. Secondly, in comparative advertising, the target may not be the competitor's product but the competitor themselves, which is called personal comparative advertising. Thirdly, the aim of comparative advertising may be to benefit from the competitor's recognition. In this case, the competitor's product or service is not denigrated. Instead, it is suggested that the quality found in these products or services is also present in their own product or service, attempting to convince consumers to purchase. Fourthly, there can be a price comparison. For a price comparison, the products should serve a similar purpose; the compared products must be comparable in terms of quality and quantity. For example, comparing a premium car with a lower-class car in terms of price would not be appropriate. In some advertisements, the advertiser claims to be 'the best' or 'the cheapest'. Such advertisements are called 'top of the league advertisements'. For these ads to be lawful, the claims made in the advertisement must be true and verifiable. Lastly, comparative advertising can include a system comparison. For instance, the differences between air travel and train travel can be illustrated in the advertisement. The lawfulness of such advertisements depends on the objectivity of the comparison and the truthful and non-deceptive presentation of pros and cons to the consumer.

The advertiser's motivation in advertising is to create a desire in the consumer to procure the product or service. Therefore, it is necessary to assess whether comparative advertising constitutes an offer in the sense of the law of obligations.

Mostly, it can be said that advertising does not carry all the necessary elements for an offer. Moreover, even if the advertisement carries all the necessary elements for an offer, it is clear that the advertiser does not intend to be legally bound. Therefore, considering the advertiser's motive in advertising, it should be determined whether the advertisement constitutes an offer or an invitation to treat.

The regulation concerning comparative advertising is found in Article 55/f.1/(a)/5 of the Turkish Commercial Code No. 6102. According to this, making comparisons that are "untrue, misleading, unnecessarily denigrating to the competitor, or benefiting from the competitor's recognition in an unnecessary manner; comparing oneself, one's goods, business outputs, activities, prices with others, or surpassing a third party by similar means" is considered unlawful comparative advertising.

As seen, being comparative does not make an advertisement unlawful per se. An advertisement becomes unlawful only if the situations specified in the article occur. The article specifies cases of comparison over the business itself, goods, business outputs, activities, and prices. However, any comparison made on any subject will turn the advertisement into comparative advertising.

In this context, it is necessary to examine unlawful comparative advertising.

When advertising, the advertiser bases on differences in quality, price, quantity, etc., between products or services. These reference points must be accurate. If they are false, it will lead to deception of the consumer, making the advertisement unlawful.

The information presented in the advertisement must be verifiable to claim its accuracy. Abstract statements cannot be evaluated in this context. Advertisements may contain various exaggerations since the advertiser wants to highlight their product or service. In these cases, whether the advertisement is unlawful should be examined in light of the specific case. If the exaggeration in the advertisement prevents the consumer from obtaining true information to a degree that it becomes misleading, the advertisement will be unlawful.

When examining the article's reasoning, advertisements that cause misunderstandings, suspicions, perceptions, thoughts in the average consumer about the advertised product, goods, activity, etc., are considered misleading advertising. Misleading can be achieved through statistical data, different pricing bases, overlooking important and influential aspects, or making comparisons between irrelevant and insignificant items.

The perception of reality in the advertisement should cover the entirety of the advertisement. Therefore, the argument used in misleading advertising may essentially be true. For instance, in the case of a car brand's advertisement stating 'now 2 years warranty in X models', since a 2-year warranty is a legal obligation, presenting it as an advantage would not be accurate. Here, the argument used is true, but the way it is used is misleading.

A similar situation applies when presenting research results in advertisements. The advertiser is not obliged to present all results objectively. However, if they only publish aspects where they are superior and completely ignore aspects where the competitor is superior, this will make the advertisement misleading and thus unlawful.

Advertisements may contain denigrating statements about competitors. The mere presence of denigration in an advertisement does not make it unlawful per se. However, advertisements that are untrue or negatively affect the competitor's image constitute unfair competition.

Advertisements can contain humor or irony. In this case, for the humor or irony not to constitute unnecessary denigration, it must not be taken seriously by the consumer, and the language used in the advertisement should not create a negative judgment about the company being addressed.

Advertisements may involve benefiting from a competitor's recognition. Naturally, for this to occur, the competitor must be recognized. It should be noted that recognition in the context of Unfair Competition Law is not the same as recognition in the context of Intellectual Property Law. Therefore, benefiting from the recognition of an enterprise known in a specific region of Turkey will constitute benefiting from recognition under Unfair Competition Law. Moreover, benefiting from the competitor's recognition must be done in a manner that violates the principle of honesty. In this context, the benefit must be unnecessary. The wording of the provision implies that there may be cases where benefiting from recognition is necessary. For example, benefiting from the recognition of a competitor's product may be necessary to explain a new invention. In such a case, it will be concluded that benefiting from recognition is necessary.