Grounds for Annulment of Arbitral Awards in Turkey: A Comprehensive Legal Guide

Introduction

Arbitration is widely used in Turkey for resolving commercial disputes arising from construction, infrastructure, energy, international trade, corporate transactions, banking, transportation, technology, distribution and investment agreements. Parties frequently choose arbitration because it offers procedural flexibility, access to specialist decision-makers, privacy and greater international enforceability than ordinary court litigation.

An arbitral award is generally final and binding. A party that disagrees with the tribunal’s factual findings, interpretation of the contract or application of substantive law cannot ordinarily file a full appeal on the merits. Turkish law instead provides a limited judicial remedy known as an action for annulment of an arbitral award, also commonly described as an action to set aside the award.

The grounds for annulment of arbitral awards in Turkey are exhaustively regulated under two principal statutes:

• Article 15 of the Turkish International Arbitration Law No. 4686, known as the MTK;
• Article 439 of the Turkish Code of Civil Procedure No. 6100, known as the HMK.

The applicable statute depends primarily on whether the arbitration is domestic or international and whether the legal seat of arbitration is located in Turkey.

The annulment court does not conduct a new trial. It does not replace the arbitrators’ assessment with its own assessment or reconsider the entire dispute. Its role is confined to examining whether one of the limited jurisdictional, procedural, arbitrability or public-policy grounds specified by law exists.

This article explains the grounds for annulment of arbitral awards in Turkey, the competent court, filing deadlines, burden of proof, effect on enforcement and practical issues that parties should consider when challenging or defending an arbitral award.

What Is an Action for Annulment of an Arbitral Award?

An action for annulment is a judicial remedy through which a party requests the Turkish court at the seat of arbitration to set aside all or part of an arbitral award.

It is fundamentally different from an appeal.

In an ordinary appeal, a higher court may review whether the lower court correctly evaluated the facts and applied the law. In an annulment action, the court generally examines only whether the arbitration complied with the essential requirements established by the arbitration agreement and applicable legislation.

Turkish legislation expressly provides that the only judicial remedy directly available against a qualifying arbitral award is an annulment action. Article 15 of the International Arbitration Law and Article 439 of the Code of Civil Procedure list the permissible grounds for setting aside an award.

The restricted nature of annulment review protects the finality of arbitration. If courts were permitted to reconsider every contractual interpretation, expert opinion or factual determination, arbitration would effectively become the first stage of an ordinary court process.

Annulment Is Not a Review of the Merits

One of the most important principles of Turkish arbitration law is that an annulment court cannot review the merits of the arbitral award.

The court should not determine:

• Whether the tribunal interpreted the contract correctly;
• Whether a witness was reliable;
• Whether an expert calculation was technically accurate;
• Whether damages should have been higher or lower;
• Whether another legal interpretation was more persuasive;
• Whether the tribunal made an ordinary error of fact or substantive law.

The Turkish Court of Cassation has repeatedly stated that the statutory grounds for annulment are exhaustive and that the legal or factual correctness of the award cannot be examined as though the annulment court were an appellate court. In particular, the courts may not investigate whether the arbitrators correctly applied substantive law merely because one party disagrees with the result.

A legal error may become relevant only where it also gives rise to an independent statutory ground, such as a serious denial of the right to be heard, excess of jurisdiction, non-arbitrability or a genuine violation of public policy.

Which Turkish Law Applies?

International Arbitration Law No. 4686

The Turkish International Arbitration Law applies principally where the dispute contains a statutory foreign element and the seat of arbitration is in Turkey. Its provisions may also apply in certain circumstances where the law has been selected by the parties or the arbitral tribunal.

A foreign element may arise where the parties have places of business in different countries, a substantial part of the contractual obligations is performed abroad, foreign capital is involved or the transaction results in cross-border movement of goods or capital.

An international commercial arbitration seated in Istanbul may therefore be governed by the MTK even where one or both parties are Turkish companies.

Turkish Code of Civil Procedure No. 6100

The domestic arbitration provisions of the Code of Civil Procedure apply where the dispute does not contain the foreign element defined by the MTK and the seat of arbitration is located in Turkey.

Article 407 of the Code of Civil Procedure expressly limits the domestic arbitration regime to disputes without a foreign element and with a Turkish seat.

Although the annulment grounds under the MTK and HMK are substantially similar, there are important procedural differences concerning the deadline, effect of filing on enforcement and waiver of the right to seek annulment.

Can Turkish Courts Annul a Foreign-Seated Arbitral Award?

As a general rule, Turkish courts set aside arbitral awards only where Turkey is the legal seat of arbitration or where Turkish arbitration law gives the Turkish courts supervisory jurisdiction.

An award rendered in an arbitration legally seated in London, Paris, Geneva, Dubai or another foreign jurisdiction is not ordinarily annulled by a Turkish court. The courts of the seat generally have authority to set the award aside.

Where enforcement of a foreign-seated award is requested in Turkey, the Turkish court may recognise and enforce the award or refuse enforcement on the limited grounds established under the New York Convention and Turkish private international law. Refusal of enforcement in Turkey is not the same as annulment of the award.

Article V of the New York Convention recognises that an award may be set aside or suspended by a competent authority in the country in which, or under the law of which, it was made. The Convention separately regulates whether that award will be recognised in another contracting state.

Accordingly, the first step in any challenge is to identify the legal seat of arbitration correctly.

Competent Court for Annulment Proceedings

International Arbitration under the MTK

Following the amendments introduced by Law No. 7101, an annulment action under Article 15 of the MTK is filed directly before the territorially competent Regional Court of Appeal, which acts as the court of first instance for the annulment case.

Territorial jurisdiction is determined by reference to the court identified under Article 3 of the MTK. In general, this is connected with the respondent’s domicile, habitual residence or place of business. If none is located in Turkey, the statutory rule refers to Istanbul. The relevant judicial function is exercised according to whether the underlying dispute falls within civil or commercial jurisdiction.

The Regional Court of Appeal’s annulment judgment may be appealed directly to the Court of Cassation.

Domestic Arbitration under the HMK

For domestic arbitration, Article 439 provides that the annulment action must be filed before the Regional Court of Appeal at the seat of arbitration.

Law No. 7101 amended Article 439 by replacing the former reference to the “court at the seat of arbitration” with an express reference to the Regional Court of Appeal at the seat.

The decision of the Regional Court of Appeal may be appealed to the Court of Cassation. Review at the Court of Cassation is likewise limited to the statutory annulment grounds.

Time Limit for Filing an Annulment Action

The filing period is short and must be calculated carefully.

Deadline under the MTK

Under Article 15 of the International Arbitration Law, an annulment action must be filed within 30 days.

The period begins when the arbitral award is notified to the party. Where a correction, interpretation or additional award is requested, the period runs from notification of the relevant subsequent decision.

Deadline under the HMK

Under Article 439 of the Code of Civil Procedure, an annulment action must be filed within one month.

The period begins upon notification of the award or the decision concerning correction, clarification or completion of the award.

The expressions “30 days” and “one month” should not automatically be treated as identical. They are different statutory formulations and must be calculated under the relevant procedural rules.

Because the deadline is strict, counsel should immediately determine:

• The exact notification date;
• The applicable arbitration statute;
• Whether any correction or additional-award application was filed;
• The competent Regional Court of Appeal;
• The final filing date.

Waiting until negotiations concerning voluntary payment have ended may result in the loss of the right to challenge the award.

Grounds for Annulment under Turkish Arbitration Law

The following grounds form the core of Article 15 of the MTK and Article 439 of the HMK.

1. Incapacity of a Party or Invalidity of the Arbitration Agreement

An award may be annulled where one of the parties to the arbitration agreement lacked legal capacity or the arbitration agreement was invalid.

Under the MTK, the validity of the arbitration agreement is assessed under the law selected by the parties to govern that agreement. If the parties made no such choice, Turkish law applies.

Potential invalidity issues may include:

• Lack of legal or corporate capacity;
• Lack of authority to execute the arbitration agreement;
• Absence of valid consent;
• Failure to satisfy the written-form requirement;
• Uncertainty regarding the parties or disputes covered;
• An arbitration clause that is inoperative or incapable of performance.

The arbitration agreement is generally treated as legally separate from the main contract. Therefore, the alleged invalidity or termination of the principal commercial agreement does not automatically invalidate the arbitration clause.

The party seeking annulment must distinguish between invalidity of the main contract and invalidity of the arbitration agreement itself.

A company alleging that its representative lacked authority should submit the relevant corporate documents, powers of attorney, signature circulars and applicable law. Merely asserting that the signatory lacked authority will not ordinarily be sufficient.

2. Improper Appointment or Constitution of the Arbitral Tribunal

An award may be annulled where the arbitrator or arbitral tribunal was not constituted in accordance with the parties’ agreement or the mandatory procedure under the applicable legislation.

Examples include:

• Appointment of the wrong number of arbitrators;
• Failure to follow an agreed nomination procedure;
• Appointment by an unauthorised institution;
• Failure to provide a party with the agreed opportunity to nominate an arbitrator;
• Appointment of a person who lacks contractually required qualifications;
• Continued participation of an arbitrator whose mandate had legally ended;
• A serious and properly preserved challenge concerning independence or impartiality.

Not every technical departure from the appointment procedure necessarily justifies annulment. The court will assess the nature of the irregularity, whether the agreed procedure was genuinely violated and whether the challenging party raised the objection at the appropriate stage.

A party that knowingly participates in the arbitration without objecting to a procedural irregularity may later face a waiver argument. Under Article 409 of the HMK, a party that continues the arbitration without timely objecting to a derogable rule or the arbitration agreement may be treated as having waived the objection.

3. Failure to Render the Award within the Arbitration Period

Turkish arbitration legislation establishes a statutory arbitration period unless the parties validly agree otherwise or the period is extended through the appropriate procedure.

An award rendered after expiry of the applicable arbitration period may be challenged.

Before relying on this ground, the applicant must examine:

• The date on which the arbitration period began;
• Any agreement extending the period;
• Institutional rules incorporated into the arbitration clause;
• Decisions of the competent court;
• Suspension periods;
• Whether the parties implicitly or expressly consented to an extension;
• The actual legal date on which the award was rendered.

A minor delay should not be assessed solely by reference to the date on which a copy of the award was received. The decisive date may be the date on which the tribunal legally rendered the award.

This ground highlights the importance of maintaining an accurate procedural chronology throughout the arbitration.

4. Unlawful Decision on Jurisdiction

An arbitral tribunal has authority to rule on its own jurisdiction under the competence-competence principle. However, its jurisdictional determination is not immune from judicial review at the annulment stage.

An award may be annulled where the tribunal unlawfully determined that:

• It had jurisdiction when no valid arbitration agreement existed;
• It lacked jurisdiction despite a valid and applicable arbitration agreement;
• A particular claim fell within or outside the arbitration clause;
• A non-signatory was bound by the arbitration agreement;
• A contractual precondition to arbitration affected jurisdiction.

Jurisdictional challenges should generally be raised during the arbitration. A party should not participate fully in the proceedings, wait for an unfavourable award and then raise an objection that could have been presented earlier.

The court’s review concerns the legal foundation of the tribunal’s jurisdiction. It does not permit a general reconsideration of the merits.

5. Decision outside the Scope of the Arbitration Agreement or Excess of Authority

The tribunal may decide only the disputes and claims submitted to it.

An award may be annulled where the tribunal:

• Decides a dispute outside the arbitration clause;
• Grants relief that was never requested;
• Determines the rights of a person not bound by the arbitration agreement;
• Decides claims arising under a contract not covered by the clause;
• Exceeds limitations expressly agreed by the parties;
• Fails to decide the entirety of a properly submitted claim.

The distinction between legal reasoning and the scope of relief is important.

A tribunal is generally free to adopt a different legal analysis from the parties’ submissions, provided that it remains within the dispute and relief submitted for decision and respects the right to be heard. An award should not be annulled merely because the tribunal relied on a legal characterisation that one party did not prefer.

Partial Annulment

Both Turkish arbitration regimes recognise the possibility of partial annulment.

If the tribunal decided matters both inside and outside the arbitration agreement, and the two parts can be separated, only the portion falling outside the arbitration agreement should be annulled. The remainder of the award may be preserved.

Partial annulment reflects the principle that courts should interfere with an award only to the extent strictly necessary.

6. Procedural Irregularity Affecting the Outcome

An award may be annulled where the arbitral proceedings were not conducted in accordance with:

• The procedure agreed by the parties;
• The selected institutional rules;
• In the absence of an agreement, the mandatory provisions of the applicable arbitration legislation.

However, the existence of a procedural irregularity alone is not always enough. Both Article 15 of the MTK and Article 439 of the HMK require a meaningful connection between the irregularity and the substance or outcome of the award.

Possible examples include:

• Refusal to apply an agreed procedure governing submissions;
• Material departure from the agreed evidentiary timetable;
• Failure to communicate decisive evidence to one party;
• Deciding the dispute before a party’s authorised submission deadline expired;
• Unjustified refusal to hear material evidence;
• Violation of a mandatory procedural rule that affected the award.

By contrast, harmless procedural errors that had no realistic effect on the decision should not ordinarily result in annulment.

The applicant should explain not only what procedural rule was violated but also how that violation materially affected its ability to present the case or the tribunal’s decision.

7. Violation of Equality or the Right to Be Heard

The parties must be treated equally and given a reasonable opportunity to present their claims and defences.

The HMK expressly refers to both the equality of the parties and the right to be heard. The MTK expressly lists failure to observe equality and also protects procedural fairness through its general procedural-irregularity framework.

A violation may arise where:

• One party receives procedural opportunities denied to the other;
• A party is not notified of a material hearing;
• Decisive evidence is considered without being disclosed;
• A party is denied a reasonable opportunity to respond to a new claim;
• The tribunal relies on a decisive legal or factual issue without giving the parties a fair chance to address it;
• The tribunal refuses to consider a submission without a legitimate procedural reason.

The right to be heard does not give a party an unlimited right to submit repetitive evidence, extend deadlines indefinitely or present every witness it proposes.

Tribunals retain authority to manage proceedings efficiently. The relevant question is whether the procedure, viewed as a whole, provided each party with a fair and reasonable opportunity to present its case.

8. Non-Arbitrability of the Dispute

An arbitral award may be annulled where the subject matter of the dispute is not capable of settlement by arbitration under Turkish law.

This ground is considered by the court on its own motion, even where the parties do not raise it.

Under Article 408 of the HMK, disputes concerning rights in rem over immovable property and matters that are not subject to the parties’ free disposition are not arbitrable. The MTK similarly excludes disputes concerning rights in rem over immovable property situated in Turkey and matters that are not subject to the parties’ will.

Most ordinary commercial claims are arbitrable, including disputes concerning:

• Contractual payments;
• Construction costs;
• Delay and disruption;
• International sales;
• Supply agreements;
• Distribution relationships;
• Share purchase contracts;
• Joint ventures;
• Licensing and technology contracts.

Special care is required for disputes involving:

• Ownership of immovable property;
• Certain corporate-status matters;
• Bankruptcy or insolvency status;
• Family status;
• Criminal liability;
• Administrative sanctions;
• Rights that cannot legally be waived or disposed of by the parties.

A contractual dispute merely connected with real estate is not necessarily non-arbitrable. For example, a contractor’s monetary claim arising from a construction contract may be arbitrable even though the works relate to a building. A direct determination of ownership or another right in rem over Turkish immovable property is materially different.

9. Violation of Turkish Public Policy

An award may be annulled where it is contrary to Turkish public policy.

Public policy is one of the most frequently invoked and most frequently misunderstood annulment grounds.

It should not be used as a general mechanism for correcting alleged mistakes in the application of law. Otherwise, every substantive-law objection could be reformulated as a public-policy argument and the prohibition against merits review would become meaningless.

Public policy may become relevant where the award’s recognition within the Turkish legal order would create a manifest conflict with fundamental legal principles.

Potential examples may include:

• Serious denial of procedural fairness;
• Enforcement of an obligation prohibited by law;
• An award resulting from corruption or fraud affecting the arbitral process;
• A result manifestly incompatible with fundamental constitutional principles;
• Disregard of mandatory legal principles of exceptional importance;
• A decision requiring conduct amounting to a criminal offence.

The mere fact that the tribunal applied foreign law, interpreted Turkish law differently or reached a commercially severe outcome does not automatically establish a public-policy violation.

Turkish Court of Cassation decisions emphasising that the merits cannot be re-examined are particularly important when assessing public-policy allegations. Public policy must remain an exceptional safeguard rather than a disguised appeal.

Burden of Proof in Annulment Proceedings

Under the MTK, the grounds are divided into two principal groups.

The party seeking annulment must generally prove grounds such as:

• Incapacity or invalidity of the arbitration agreement;
• Improper appointment of arbitrators;
• Expiry of the arbitration period;
• Unlawful jurisdictional decision;
• Excess of authority;
• Material procedural irregularity;
• Failure to observe equality.

The court examines non-arbitrability and public policy on its own motion.

Although Article 439 of the HMK is structured differently, the applicant should still provide concrete facts and evidence supporting the grounds on which it relies. The court does not conduct an unlimited investigation to identify possible defects in the arbitration.

A properly prepared annulment petition should connect each alleged fact to a specific statutory ground and explain its material legal effect.

Does Filing an Annulment Action Suspend Enforcement?

The answer differs between international and domestic arbitration.

International Arbitration under the MTK

Filing an annulment action under Article 15 of the MTK automatically suspends enforcement of the arbitral award.

The award ordinarily becomes enforceable after the annulment action has been rejected and the relevant enforceability requirements have been completed, or after the period for seeking annulment has expired.

Domestic Arbitration under the HMK

Filing an annulment action under Article 439 does not automatically suspend enforcement.

A party may request suspension, but it must provide security covering the value of the money or property awarded, subject to the court’s determination. An appeal against the Regional Court of Appeal’s judgment also does not automatically suspend execution.

This distinction can have significant practical consequences for asset-preservation and enforcement strategy.

Waiver of the Right to Seek Annulment

The MTK contains a specific mechanism permitting qualifying parties whose domicile or habitual residence is outside Turkey to waive all or part of the right to seek annulment.

The waiver must be made through an express statement in the arbitration agreement or through a subsequent written agreement.

Even where a waiver exists, non-arbitrability and public policy remain relevant when an enforceability certificate is requested because the court is required to examine these matters on its own motion.

There is no identical general advance-waiver mechanism under the HMK for domestic arbitration.

Parties should therefore avoid using a generic waiver clause without analysing whether:

• The parties satisfy the statutory residence requirements;
• The wording is sufficiently clear;
• The waiver covers all or only specified grounds;
• The clause is consistent with the selected institutional rules;
• The commercial consequences have been fully considered.

Court Procedure and Appeal

Annulment cases must be heard on a priority and expedited basis.

Unless the Regional Court of Appeal decides otherwise, the application may be examined on the written file without an oral hearing.

The decision may be appealed to the Court of Cassation. Review before the Court of Cassation is limited to the statutory grounds for annulment and is likewise intended to be conducted promptly.

The appeal should not simply repeat the party’s arguments on the underlying contract. It should identify how the Regional Court of Appeal incorrectly applied or interpreted a specific annulment ground.

Consequences of Annulment

The court may:

• Reject the annulment action;
• Annul the entire award;
• Annul only a separable part of the award.

The legal consequences depend on the ground of annulment.

In certain cases, the parties may recommence arbitration, reappoint the same or different arbitrators and determine a new arbitration period, unless they have agreed otherwise. Both the MTK and HMK contain provisions preserving the parties’ original intention to arbitrate for specified annulment grounds.

Where the award is annulled because no valid arbitration agreement exists or the dispute is non-arbitrable, commencing a new arbitration may not be legally possible.

The parties should therefore examine the precise reasoning of the annulment judgment before deciding whether to return to arbitration or pursue another legal remedy.

International Effect of Annulment in Turkey

An award annulled by a Turkish court may encounter enforcement difficulties in other countries.

Article V(1)(e) of the New York Convention permits a foreign enforcement court to refuse recognition where the award has been set aside or suspended by a competent authority in the country in which, or under the law of which, the award was made.

Where annulment proceedings remain pending, Article VI permits the enforcement court to adjourn its decision and, where appropriate, order the award debtor to provide security.

The international enforcement consequences should therefore be considered when deciding whether to seek annulment, negotiate settlement or commence enforcement in another jurisdiction.

Practical Recommendations for Challenging an Award

A party considering an annulment action should act immediately after receiving the award.

The legal team should:

1. Confirm the seat and applicable arbitration legislation;
2. Record the exact date of notification;
3. Review any correction, interpretation or additional-award procedure;
4. Identify the competent Regional Court of Appeal;
5. Separate merits complaints from statutory annulment grounds;
6. Review all procedural orders and hearing records;
7. Identify objections raised during the arbitration;
8. Collect evidence demonstrating material prejudice;
9. Consider enforcement and asset risks;
10. File before the statutory period expires.

A weak annulment petition often describes why the tribunal’s conclusion was allegedly wrong but fails to connect the complaint to a statutory ground.

A persuasive petition should instead explain:

• Which statutory ground applies;
• Which specific procedural or jurisdictional event created the violation;
• When the objection was raised;
• What evidence proves it;
• How the violation affected the award;
• Whether total or partial annulment is requested.

Practical Recommendations for Defending an Award

The party defending the award should emphasise:

• The exhaustive nature of annulment grounds;
• The prohibition against reviewing the merits;
• Any failure by the applicant to object during arbitration;
• The tribunal’s procedural discretion;
• The absence of material prejudice;
• The distinction between a legal error and public policy;
• The severability of any allegedly defective portion;
• The applicant’s attempt to reargue the underlying dispute.

The defence should demonstrate that the applicant received a reasonable opportunity to present its case and that the tribunal acted within the arbitration agreement.

Frequently Asked Questions

Can an arbitral award be annulled because the tribunal applied Turkish law incorrectly?

An ordinary error in interpreting or applying Turkish law is not, by itself, a statutory annulment ground. It may become relevant only if it also creates a genuine violation of public policy or another specific ground.

Can the court recalculate damages?

No. The annulment court does not ordinarily recalculate damages or reassess expert evidence.

Can only part of an award be annulled?

Yes. Where the defective part can be separated from the remainder, partial annulment is possible.

Does an annulment action automatically suspend enforcement?

Under the MTK, filing the action automatically suspends enforcement. Under the HMK, it does not; suspension may be requested subject to security.

Where is the annulment action filed?

It is filed directly before the competent Regional Court of Appeal. Under the HMK, this is the Regional Court of Appeal at the seat of arbitration. Under the MTK, territorial jurisdiction is determined through the statutory reference to Article 3.

How long is the filing period?

The MTK provides 30 days. The HMK provides one month. The period generally begins upon notification of the award or the relevant correction, interpretation or completion decision.

Is public policy the same as an incorrect legal decision?

No. Public policy concerns fundamental principles of the Turkish legal order and should not be used as a substitute for merits review.

Can Turkish courts annul an award seated abroad?

Ordinarily, no. Turkish courts may examine recognition and enforcement of a foreign award, while annulment is generally handled by the competent court at the seat.

Conclusion

The grounds for annulment of arbitral awards in Turkey are limited and exhaustive.

International arbitral awards seated in Turkey are principally governed by Article 15 of the Turkish International Arbitration Law No. 4686. Domestic awards seated in Turkey are governed by Article 439 of the Turkish Code of Civil Procedure No. 6100.

An award may be annulled on grounds including incapacity, invalidity of the arbitration agreement, improper constitution of the tribunal, expiry of the arbitration period, unlawful jurisdictional findings, excess of authority, material procedural irregularity, violation of equality or the right to be heard, non-arbitrability and public policy.

The annulment court does not conduct a new trial and cannot reconsider the merits merely because one party believes that the arbitrators misunderstood the evidence, interpreted the contract incorrectly or applied substantive law improperly.

Parties must also pay close attention to procedure. The action must be filed before the competent Regional Court of Appeal within the short statutory period. The MTK provides a 30-day period, while the HMK provides one month.

A successful annulment strategy requires precise classification of the award, careful identification of a statutory ground, preservation of procedural objections and clear proof of material prejudice.

Conversely, a party defending an award should insist on the finality of arbitration and prevent ordinary merits arguments from being repackaged as jurisdictional or public-policy complaints.

Because annulment proceedings may affect both enforcement in Turkey and recognition abroad, businesses should obtain specialised Turkish arbitration advice immediately after the award is notified.