What Is a Rent Determination Lawsuit Based on Market Value? (2025 Guide)

In today’s rapidly changing rental market in Turkey, one of the most common questions asked by both landlords and tenants is how a rent determination lawsuit works. Especially when a rental agreement completes its fifth year, the rent can be legally adjusted according to current market conditions. In this comprehensive guide, we explain everything you need to know about a rent determination lawsuit in Turkey in a clear, simple, and up-to-date format.

What Is a Rent Determination Lawsuit?

A rent determination lawsuit is a legal action filed to have the court set a new rental amount for residential or commercial properties after the lease completes five years. The court determines the new rent according to the current market value (fair market rent), ensuring that the amount is fair, reasonable, and aligned with current rental conditions.

Who Can File a Rent Determination Lawsuit in Turkey?

The following parties may file a rent determination lawsuit in Turkey:

• The tenant
• The landlord (lessor)
• The property owner (if different from the landlord)
• Any co-owner (in shared ownership)
• All heirs (in joint undivided inheritance; all heirs must participate or authorize one heir)

Both tenants and landlords have equal legal standing to file a rent determination lawsuit in Turkey. The law does not grant an exclusive right to only one side.

Legal Basis: Article 344/3 of the Turkish Code of Obligations

The legal basis for rent determination lawsuits in Turkey is found in Article 344/3 of the Turkish Code of Obligations (TCO). When a lease exceeds five years, the court considers the following criteria when determining the rent:

• The 12-month average of the Consumer Price Index (CPI)
• Comparable rental values (market rent) in the same area
• The condition and characteristics of the property
• General principles of equity

The court evaluates all these factors together and determines a new rent that is fair and in line with the market conditions.

When Can a Rent Determination Lawsuit Be Filed?

A rent determination lawsuit must generally be filed no later than 30 days before the start of the new rental year. However, if the tenant has been served with a formal notice (typically via notary) within this 30-day timeframe, the lawsuit may be filed any time until the end of that rental year.

Example Timeline

Lease start date: 01/01/2020
Five-year period ends: 01/01/2025

Depending on the circumstances:

• If there is no rent increase clause in the lease → the lawsuit must be filed at least 30 days before the new rental period, i.e. by 01/12/2024.
• If there is a valid rent increase clause in the lease, or the tenant has been served with a notice → the rent determination lawsuit can be filed any time between 01/01/2025 and 31/12/2025.

Is Sending a Notice Mandatory?

Sending a formal notice is not mandatory in order to file a rent determination lawsuit in Turkey. However, a properly served notice extends the time period within which the lawsuit may be filed, often up to the end of the relevant rental year. For this reason, it can be a practical and strategic step in many cases.

Is Mediation Mandatory in Turkey?

Yes. Before filing a rent determination lawsuit in Turkey, mandatory mediation must be concluded.

If the parties reach an agreement during mediation, the agreement becomes binding and there is no need to proceed with a lawsuit. If no agreement is reached, a “non-settlement report” is issued by the mediator, and this report must be submitted to the court when filing the rent determination lawsuit.

Costs of a Rent Determination Lawsuit in 2025

Average litigation costs for a rent determination lawsuit in Turkey in 2025 are as follows:

• Initial filing fees: approximately 5,000 TL
• Expert and on-site inspection (discovery) fees: approximately 15,000 TL

These amounts are indicative and may vary depending on factors such as:

• The number of parties involved
• The difference between the current rent and the rent requested
• The duration and complexity of the proceedings
• Annual increases in court fees and related expenses

How Is the Court Fee (Value of the Claim) Calculated?

The court fee is calculated based on the difference between the current rent and the rent requested in the lawsuit.

Example Calculation

Current monthly rent: 10,000 TL
Requested monthly rent: 25,000 TL
Difference: 15,000 TL

In this example, court fees are calculated based on 15,000 TL. Therefore, it is important to determine the requested rent carefully before filing the lawsuit.

Can the Requested Rent Be Increased Later During the Case?

No. In rent determination lawsuits in Turkey, it is generally not possible to amend the claim later in order to increase the requested rent. For this reason, the initial rent amount requested should be calculated and set very carefully at the time of filing.

What Is the “Equity Discount” (Long-Term Tenant Discount)?

In practice, once the expert has determined a market-value-based rent, the court often applies an equity discount in the range of 5% to 20%. This is commonly referred to in practice as the “long-term tenant discount”. This approach is supported by established case law (including Court of Cassation / Yargıtay precedents).

Can Market-Value-Based Rent Be Requested Before the 5-Year Period Ends?

A rent determination lawsuit may technically be filed before the expiry of five years; however, in such cases the court cannot determine the rent based on full market value. Instead, the rent can only be adjusted in line with the 12-month CPI average and other limits set by law.

Rent Adjustment Lawsuit vs. Rent Determination Lawsuit

A rent determination lawsuit and a rent adjustment (adaptation) lawsuit are often confused, but they are legally distinct remedies under Turkish law.

• Rent determination lawsuit: Focuses on setting the rent according to market value once the five-year period has passed, based primarily on TCO Article 344.
• Rent adjustment (adaptation) lawsuit: Based on TCO Article 138, and may be filed when extraordinary economic changes significantly disturb the contractual balance existing at the time the lease was signed.

Which Court Is Authorized in a Rent Determination Lawsuit?

In Turkey, rent determination lawsuits must be filed before the Civil Court of Peace (Sulh Hukuk Mahkemesi) located in the jurisdiction where the leased property is situated.

Is Hiring a Lawyer Mandatory?

Hiring a lawyer is not legally mandatory in rent determination lawsuits in Turkey. However, due to strict time limits, procedural requirements and the importance of correctly assessing the requested rent, working with an experienced attorney in this field is highly recommended to avoid procedural mistakes and loss of rights.

Conclusion

A rent determination lawsuit based on market value is an essential legal tool in Turkey for ensuring that rental prices reflect current market conditions once a lease completes its five-year period. Both landlords and tenants should pay close attention to timing, procedural steps, and the calculation of the requested rent amount.

If you are considering filing a rent determination lawsuit in Turkey, obtaining professional legal advice before initiating the process will greatly help to protect your rights and ensure that the case proceeds efficiently and correctly.