1.)  Conditions for a Rent Determination Lawsuit Under Article 344/3 of the Turkish Code of Obligations

Pursuant to Article 344/3 of the Turkish Code of Obligations (“TCO”), where the lease relationship exceeds five years or is renewed after the expiration of five years, the court may redetermine the rent by taking into account comparable rental values, the characteristics of the leased property, and principles of equity.

Accordingly, one of the most important issues in rent determination lawsuits is identifying the date from which the five-year period should be calculated.

2.) Do Supplementary Agreements Increasing the Rent Reset the Five-Year Period?

According to the case law of the Court of Cassation and the Regional Courts of Appeal, a mere amendment of the rent amount does not automatically establish a new lease agreement.

In particular, in a 2020 decision of the Bursa Regional Court of Appeal, it was held that a subsequent agreement increasing the rent did not reflect market and comparable rental values. Therefore, the court concluded that the initial lease agreement should be taken as the basis for calculating the five-year period.

Accordingly, where:

• only the rent amount is amended;
• the other essential terms of the lease remain unchanged; and
• the newly determined rent does not correspond to comparable market rental values,

the commencement date of the original lease agreement may continue to be used for calculating the five-year period.

3.) In Which Cases Is a New Lease Agreement Deemed to Exist?

Courts primarily examine whether the parties intended to continue the existing lease relationship or to enter into an entirely new lease agreement.

In a 2024 decision of the Trabzon Regional Court of Appeal, the following circumstances led the court to conclude that the second agreement constituted a new and independent lease agreement:

• modification of the lease term;
• redetermination of the rent amount; and
• manifestation of an intention by the parties to enter into a new contractual relationship.

In such cases, the five-year period starts anew, and a rent determination lawsuit under Article 344/3 of the TCO cannot be filed until five years have elapsed from the execution of the new agreement.

4.) Consequences of a Rent Amount That Is Not Consistent with Comparable Market Values

According to the settled case law of the Court of Cassation, where the rent specified in a renewed agreement is not consistent with comparable market rental values, the commencement date of the original lease agreement may still be taken into account, even if five years have not passed since the execution of the subsequent agreement.

This approach is particularly important where the rent remains significantly below prevailing market conditions. In a decision of the İzmir Regional Court of Appeal, the court held that although a second agreement had been executed, the rent stipulated therein was not consistent with comparable market values and therefore redetermined the rent based on principles of equity.

5.) The Position of the Court of Cassation

In a 2016 decision, the 6th Civil Chamber of the Court of Cassation expressly stated that if the rent stipulated in a renewal agreement is not compatible with comparable market rental values, the period elapsed since the commencement of the original lease agreement may be considered, even if five years have not passed since the execution of the renewal agreement.

Accordingly, in each individual case, the following factors must be examined separately:

1. Whether the second agreement constitutes a new lease agreement;
2. Whether the agreed rent is consistent with comparable market values; and
3. The nature of the parties’ contractual intent.

6.) Can the Parties Agree Not to File a Rent Determination Lawsuit?

According to the prevailing view in legal doctrine, a landlord may undertake not to seek a rent increase based on comparable rental values at the end of the five-year period. Such an undertaking is generally considered valid and binding.

In that event, the landlord may only seek an increase in rent by filing a rent adaptation (hardship) lawsuit, alleging the existence of extraordinary circumstances and proving that the legal conditions for adaptation have been satisfied.

Conclusion

Not every subsequent agreement concerning the rent amount restarts the five-year period prescribed under Article 344/3 of the Turkish Code of Obligations. The decisive factors are whether the transaction constitutes a new lease agreement and whether the newly agreed rent is consistent with comparable market rental values.

Therefore, before filing a rent determination lawsuit, the contents of the relevant agreements, the provisions amended by the parties, their contractual intent, and comparable market rental values should all be carefully examined, and a case-specific legal assessment should be conducted.