Learn how rent increase rules work in Turkey, including CPI limits, five-year rent determination lawsuits, foreign-currency leases, mandatory mediation, and practical advice for landlords and tenants.
Introduction
Rent increase disputes are among the most common legal conflicts in Turkey because they sit at the point where inflation, housing pressure, contractual freedom, and tenant protection collide. In Turkish law, rent is not increased simply because the landlord believes the market has moved. For residential and roofed workplace leases, the main framework comes from Article 344 of the Turkish Code of Obligations, which sets the general ceiling for ordinary renewal increases and creates a different court-based mechanism after the fifth year. In addition, Turkey introduced mandatory mediation for most lease disputes from 1 September 2023, and the special temporary 25% cap that applied only to certain residential renewals ended on 1 July 2024.
That means a legally sound analysis of rent increases in Turkey now requires at least five separate questions. First, is the lease one of the leases covered by the residential and roofed workplace regime? Second, is there a valid increase clause in the contract? Third, is the dispute still within the ordinary CPI-capped renewal stage, or has the five-year rent determination regime become available? Fourth, is the rent denominated in Turkish lira or foreign currency? Fifth, if there is already a dispute, was the correct pre-suit path followed and was the case filed on time?
This article explains rent increase rules in Turkey in a way that is publication-ready, SEO-oriented, and grounded in the current official legal texts. It is written for landlords, tenants, investors, property managers, and foreign readers who want a practical legal guide rather than a simplistic slogan such as “the landlord can raise the rent only once a year.” The real position is more technical, and the details matter.
1. Which Leases Are Covered by the Main Rent Increase Rules?
The starting point is Article 339 of the Turkish Code of Obligations. It states that the rules on residential and roofed workplace leases apply to these premises and to movable items left for the tenant’s use together with them. The same official text also makes clear that these rules generally apply to public-sector leases as well, except for certain short-term temporary-use situations. In practice, this means that the core rent increase rules in Article 344 govern the vast majority of ordinary apartment leases and most enclosed business leases such as shops, offices, and similar workplaces.
This matters because many people assume commercial leases are entirely free from statutory limits. They are not. Article 344 sits inside the chapter on residential and roofed workplace leases, so its logic reaches both categories. The main difference is historical: for workplace leases where the tenant was a merchant or a public/private legal entity, certain tenant-protective provisions, including Articles 343, 344, 346, and 354, were postponed for eight years from 1 July 2012 under Law No. 6217. That postponement has already expired, which means the modern rent-increase framework now applies fully to current workplace lease practice as well.
2. The General Rule: Ordinary Renewal Increases Cannot Exceed the 12-Month Average CPI Rate
The most important sentence in the current system appears in Article 344. The official text states that agreements on the rent amount to be applied in renewed lease periods are valid provided they do not exceed the rate of change in the twelve-month average consumer price index for the previous rental year. The same text adds that this rule also applies to leases longer than one year. In other words, if the contract says the rent will rise by 60% but the applicable twelve-month average CPI figure is lower, the clause is enforceable only up to the statutory ceiling, not up to the contractual number.
This is the core legal limit for ordinary rent renewals in Turkey today. It does not mean the landlord must always increase by the full CPI figure. The parties may agree on a lower number, and the landlord may choose a lower number. But an increase above the statutory ceiling is not saved merely because it appears in the contract. For that reason, one of the most common drafting mistakes in Turkish lease practice is using a fixed annual increase clause without checking Article 344’s mandatory ceiling.
3. What Happens If the Contract Has No Increase Clause?
Article 344 also regulates the situation where the lease does not contain a valid rent-increase clause. The official text states that if the parties made no agreement on this point, the rent is determined by the judge, again without exceeding the twelve-month average CPI change, while also taking the condition of the leased property into account and deciding according to equity. This is a very important nuance. The absence of an increase clause does not mean rent stays frozen forever; it means the adjustment path becomes judicial rather than purely contractual.
In practical terms, this means that landlords should not assume silence in the contract gives them unrestricted bargaining power at renewal, and tenants should not assume silence makes any later increase impossible. The statute fills that gap. Still, until a court determination or a lawful agreement exists, the legal debate usually turns on timing, notice, and proof rather than on informal market discussions.
4. The Fifth-Year Rule: When the Court Can Look Beyond CPI
The most litigation-sensitive part of Article 344 is its third paragraph. The official text states that regardless of whether the parties agreed on an increase clause, in leases lasting more than five years or renewed after five years, and at the end of each subsequent five-year period, the new rent for the upcoming rental year is determined by the judge by considering the twelve-month average CPI change, the condition of the leased property, and comparable rents, and by setting the amount in an equitable manner. It then adds that after each five-year period, the rent may again be adjusted under the earlier principles for the following years.
This is where court practice becomes especially important. In the ordinary renewal stage, the dispute is usually about whether the contractual increase exceeds the CPI ceiling. After the fifth year, the litigation becomes broader because the court is no longer limited to a mechanical CPI-only update. At that stage, comparable rentals, the actual condition and characteristics of the premises, and equity move to the center of the file. In practice, this is why rent determination lawsuits often become document-heavy and expert-report-heavy after the fifth year. That practical result follows directly from the criteria the statute itself requires the judge to evaluate.
For landlords, the fifth-year rule is often the first serious opportunity to argue that the legal rent has fallen far below the market. For tenants, it is the point at which relying only on the CPI ceiling becomes less protective, because the statute itself allows the court to take a wider view. That does not mean the court simply grants “market rent” without discipline. It means the court works within a broader statutory test that includes CPI but is not exhausted by CPI.
5. Foreign-Currency Rent: A Different Rule Under Article 344
Article 344 contains a separate rule for rents agreed in foreign currency. The official text states that, subject to the Law on the Protection of the Value of Turkish Currency, if the rent was agreed in foreign currency, no change can be made in the rent until five years have passed. The article also expressly preserves the rule on hardship under Article 138 of the Code. After five years, the official text says the rent is determined by applying the third-paragraph framework while also considering changes in the value of the foreign currency.
This is a major legal distinction. In Turkish-lira leases, ordinary renewals are capped by the twelve-month average CPI rule. In foreign-currency leases, the statute instead imposes a five-year lock, subject to hardship, and then shifts to a broader reassessment model after five years. For that reason, foreign-currency lease disputes require a two-layer analysis: first Article 344, and second the separate currency-control rules under Treasury legislation.
6. Currency-Control Rules: Many Domestic Real Estate Leases Cannot Be Indexed to Foreign Currency at All
Even if Article 344 recognizes the concept of foreign-currency rent, Treasury rules limit when such clauses may be used. The current Treasury communiqué states that persons resident in Turkey, contracting among themselves, may not denominate or index to foreign currency the payment obligations in real estate lease agreements relating to immovables located in Turkey, including residential and roofed workplace leases. The same communiqué also contains exceptions, including where the tenant or buyer is a Turkey-resident person without Turkish citizenship, or where other listed exception categories apply.
This means rent-increase analysis in Turkey is not complete unless the lawyer first asks whether the foreign-currency clause was even lawful under the Treasury rules. In many ordinary domestic leases between Turkey-resident parties, the answer is no. In certain exception cases, the answer may be yes. That is why the legality of the currency denomination itself is a threshold issue before one even reaches Article 344’s five-year foreign-currency logic.
7. The Temporary 25% Residential Rent Cap Was Exceptional and Has Ended
A great deal of public confusion still comes from the temporary 25% cap. The official legal text shows that this was a temporary rule added first for the period up to 1 July 2023, then extended for residential leases renewed between 2 July 2023 and 1 July 2024. The law expressly stated that, for those residential renewals, agreements were valid only up to 25% of the previous year’s rent, unless the twelve-month average CPI change was lower. The same text also stated that any amount above the cap was invalid to the extent of the excess.
That rule was exceptional, temporary, and residential only. It is no longer the general rule after 1 July 2024. Today, the system has returned to the ordinary Article 344 framework, which means the relevant ceiling is again the twelve-month average CPI for ordinary renewal periods, not a permanent 25% number. Any article, broker statement, or social-media summary that still presents 25% as the permanent nationwide rent cap is outdated.
8. When Should a Rent Determination Lawsuit Be Filed?
Article 345 provides the procedural framework for rent determination lawsuits. The official text states that a lawsuit for determination of rent may be filed at any time. But it adds an important effect rule: for the court-determined rent to bind the tenant from the beginning of the new rental period, the case must be filed at least thirty days before the start of that new period, or the landlord must have served a written notice within that same period stating that the rent will be increased. If one of those conditions is satisfied, and the case is filed by the end of the new rental period, the rent determined by the court binds the tenant from the start of that new period. The article also says that where the contract already contains a clause that rent will be increased in the new rental period, a case filed by the end of that new period will also apply from the beginning of the new period.
This is one of the most practical timing rules in Turkish lease law. The landlord may technically file “at any time,” but not every filing time has the same financial effect. If the landlord wants the new rent to operate from the start of the new rental year, missing the thirty-day pre-period window can be costly unless there is a contract clause or timely written notice preserving that effect. For tenants, Article 345 is equally important because it creates a strong timing-based defense against attempts to impose retroactive increases without the statutory preconditions.
9. Mandatory Mediation Now Covers Most Lease Disputes
Since 1 September 2023, lease disputes generally require pre-suit mediation. Article 18/B of the Law on Mediation in Civil Disputes states that, except for the provisions on eviction of leased immovables through non-judgment enforcement under Law No. 2004, disputes arising from the lease relationship are subject to mandatory mediation before suit. The same official text also shows that the provision entered into force on 1 September 2023.
For rent increase disputes, this means that many disagreements over renewal increases, rent determination, overpayment, and related lease claims cannot safely go straight to court without first passing through mediation. The procedural consequence matters just as much as the substantive law: even a strong Article 344 argument can be delayed or dismissed if the claimant ignores the mediation condition.
10. Contract Clauses That Often Mislead Parties
Another important rule is Article 343. The official text states that, in lease agreements, apart from determination of the rent amount, changes cannot be made against the tenant. Article 346 goes even further and states that the tenant cannot be burdened with payment obligations other than rent and ancillary expenses; it specifically declares invalid agreements requiring a penalty clause for late payment or making future rents immediately due because of delay.
These provisions matter in rent-increase disputes because some leases try to pressure tenants with extreme clauses: automatic punitive markups, hidden service burdens, or acceleration language disguised as an “increase mechanism.” Turkish law does not permit every such device. A contract may say many things, but if the clause conflicts with Articles 343 or 346, the statutory protection can override the drafting.
11. What “Court Practice” Usually Means in Rent Increase Cases
When lawyers in Turkey speak about “court practice” in rent increase cases, they usually mean how judges apply Articles 344 and 345 in real disputes. Based on the statutory structure, three issues tend to dominate. First, is the case still in the ordinary CPI-capped stage, or has the fifth-year framework opened the door to a broader judicial assessment? Second, were the timing and written-notice requirements in Article 345 satisfied so that the new rent can take effect from the start of the rental year? Third, if the case falls under the five-year regime, what do comparable rents, the condition of the premises, and equity indicate? Those are not extra-textual judicial inventions; they are the very criteria the statute directs the court to examine.
In practical litigation, that usually means the better-prepared party is the party with the better file. A landlord claiming that the existing rent is now far below the market will usually need credible comparables and a coherent explanation of why the property’s present legal and physical condition justifies a reset. A tenant resisting a drastic increase will usually focus on the timing of the action, the quality of the comparables, the actual condition of the unit, and the continued relevance of CPI and equity. That practical pattern flows directly from the official statutory criteria.
12. Practical Advice for Landlords
For landlords, the safest first step is to classify the file correctly. If the lease is still within the ordinary renewal stage, focus on the CPI ceiling and avoid demanding an amount above what Article 344 allows. If the lease has passed the fifth year, consider whether a rent determination lawsuit is commercially worthwhile and whether the evidence on comparables is strong enough to justify litigation. If the landlord wants the court-determined rent to bind from the start of the new rental year, do not ignore the thirty-day timing rule in Article 345.
Landlords should also check whether the lease contains a foreign-currency clause and, if so, whether that clause is lawful under Treasury rules. In many ordinary domestic leases it will not be. Where mediation is required, the landlord should treat the mediation stage as part of the litigation strategy rather than as a formality. And where the lease uses legacy wording dating from the pre-2020 workplace-transition period, that wording should be re-read in light of the fact that the eight-year postponement has ended.
13. Practical Advice for Tenants
For tenants, the first question should be whether the landlord’s proposed increase is still within the ordinary Article 344 ceiling or whether the landlord is really asking for a court-based adjustment after five years. If the case is still in the ordinary renewal stage, a demand that exceeds the twelve-month average CPI ceiling is legally vulnerable. If the lease is beyond five years, the tenant should examine whether the landlord has actually taken the proper judicial route and whether the procedural conditions in Article 345 were followed.
Tenants should also be cautious about accepting informal side documents that appear to waive statutory protection. Article 343 limits tenant-unfavorable modifications, and Article 346 invalidates certain late-payment penalty and acceleration arrangements. Finally, tenants should not overlook mandatory mediation. A strong statutory defense can lose force if the procedural path is mishandled.
14. Common Mistakes
The most common legal mistake is relying on the old 25% cap as though it still governed all residential rent increases today. It does not; it was temporary and ended for renewals after 1 July 2024. Another frequent mistake is treating every commercial lease as fully outside tenant-protective rent rules, even though the postponement regime for qualifying workplace leases has long expired. A third mistake is confusing a lawful ordinary CPI increase with a fifth-year rent determination case and assuming the same calculation method governs both.
A fourth mistake is ignoring Article 345’s timing rules and then being surprised that the judicially fixed rent does not operate from the date the landlord expected. A fifth is assuming that a foreign-currency clause is automatically valid because the contract says so, without checking the Treasury restrictions and exceptions. A sixth is going straight to court without satisfying the current mandatory mediation requirement where it applies.
Conclusion
Rent increase rules in Turkey are more structured than many landlords and tenants assume. The basic rule for ordinary renewals in residential and roofed workplace leases is the twelve-month average CPI ceiling in Article 344. If there is no increase clause, the judge may still determine the rent within that framework. After the fifth year, however, the law opens a broader judicial mechanism that allows the court to consider CPI, the condition of the premises, comparable rents, and equity together. For foreign-currency rents, Article 344 creates a separate five-year rule, but Treasury law may prevent many domestic real estate leases from being denominated in foreign currency in the first place.
The practical lesson is that rent disputes in Turkey are won less by slogans and more by classification, timing, documentation, and procedural discipline. The landlord who knows whether the dispute is a CPI-cap issue or a five-year determination case starts from a much stronger position. The tenant who knows the difference between an expired temporary cap and the current Article 344 regime is equally protected. And both sides must now remember that, in most lease disputes, the path to court runs through mandatory mediation first.
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