Criminal Appeals in Turkey: İstinaf, Temyiz & AYM Guide

Criminal appeals in Turkey have become one of the most consequential procedural battlegrounds for foreign defendants, multinational executives, and high-net-worth individuals confronting criminal exposure within Turkish jurisdiction. From a fake-invoice conviction under VUK 359 to a fraud sentence under TCK 158, the distance between an unfavourable first-instance verdict and a final, enforceable sentence is governed by a tightly choreographed appellate architecture: İstinaf at the Regional Court of Justice (Bölge Adliye Mahkemesi), Temyiz at the Court of Cassation (Yargıtay), an Individual Application to the Constitutional Court (Anayasa Mahkemesi), and — when domestic remedies are exhausted — an application to the European Court of Human Rights in Strasbourg. Missing a single 15-day window can lock in a sentence that destroys a career, dismantles a corporate structure, and triggers cross-border consequences across asset registries, banking relationships, and immigration files.

For foreign principals operating in Turkey, the appellate path is not a back-office formality — it is the single most important risk-mitigation instrument once a conviction is rendered at first instance. Foreign defendants disproportionately encounter procedural ambiguity, language barriers, and an evidentiary record built without the cross-border framing that an international standard of defence demands. Istanbul Attorneys, through its Lexin Legal strategic alliance and senior English-speaking counsel serving clients from 40+ countries, deploys appellate strategies designed to preserve every procedural objection during trial, frame appeal grounds with appellate-court precision, and escalate — when warranted — to constitutional and supranational forums.

Key Takeaways

• The İstinaf appeal window is 15 days from notification of the reasoned judgment under Article 273 of CMK No. 5271 — missing this deadline finalises the sentence and forecloses every higher remedy.

• Temyiz at the Court of Cassation is generally available only for sentences exceeding five years of imprisonment or specific catalogue offences, and reviews questions of law rather than retrying facts.

• A Constitutional Court Individual Application (bireysel başvuru) must be filed within 30 days of exhausting ordinary remedies and may obtain a retrial, financial compensation, or recognition of a rights violation.

• The European Court of Human Rights remains available for applications filed within four months of the Constitutional Court's final decision under Article 35 of the Convention.

• Strategic appellate counsel begins at the trial stage — appellate success rates are determined by the procedural objections preserved on the trial record, not by the strength of the appeal brief alone.

The Turkish Criminal Appeals Architecture

The Turkish criminal-appeals architecture rests on a four-tier review system designed to test both the factual reconstruction of the offence and the legal qualification adopted by the trial court. Codified principally in the Criminal Procedure Code (CMK) No. 5271, the framework provides one ordinary appeal that re-examines facts and law, a cassation-style review of legal compliance, and two extraordinary remedies that test the conviction against constitutional and Convention rights.

First-Instance Conviction and Why Trial Strategy Determines Appeal

The single most important factor influencing appellate success is the trial record itself. Every procedural objection, every motion to exclude evidence, every challenge to expert reports, and every formal request for translation or consular access must be entered into the court clerk's minutes (zabıt) verbatim. An objection raised orally but not recorded is, for appellate purposes, an objection that did not occur. This is why our team-defence approach — one attorney conducting cross-examination while a second monitors the minutes — is structurally indispensable for Heavy Penal cases involving foreign defendants.

Three Domestic Tiers Plus Strasbourg

Once a conviction is entered at first instance, three formal review tiers become available within the Turkish system: ordinary appeal at İstinaf, cassation at Temyiz, and constitutional review at the Anayasa Mahkemesi. A fourth, supranational tier — the European Court of Human Rights — remains accessible after domestic remedies are exhausted. Each tier has distinct admissibility criteria, scope of review, and remedial powers that experienced counsel must calibrate at the moment the first-instance verdict is delivered.

İstinaf — Regional Court of Justice (Bölge Adliye Mahkemesi)

The 15-Day Filing Window and Procedural Requirements

Under Article 273 of CMK No. 5271, the appeal to the Regional Court of Justice must be filed within 15 days of the notification of the reasoned judgment (gerekçeli karar). This deadline is jurisdictional and cannot be extended on grounds of language, illness, or absence from Turkey absent strictly construed exceptions. The petition (istinaf dilekçesi) must specify each ground of appeal in writing and identify the procedural or substantive errors alleged at first instance.

Scope of Review — Both Fact and Law

Unlike pure cassation review, the Regional Court of Justice may re-examine facts, hear new evidence, conduct a fresh hearing where necessary, and substitute its own factual findings for those of the trial court. This dual-character review is the appellate moment when a foreign defendant may, for the first time, present a reframed evidentiary case supported by translated documents, expert reports, and witnesses that were procedurally excluded at first instance. Counsel must approach the istinaf brief as a structured re-litigation rather than a perfunctory recital of trial-court errors.

Possible Outcomes

The court may affirm the conviction, modify the sentence, vacate the conviction and order acquittal, or remand the case for retrial. In our practice, modifications and partial vacaturs are statistically more common than full reversals, but each can produce decisive consequences for asset seizures, professional disqualifications, and immigration status. A reduction below the imprisonment threshold for non-deferred execution can transform the practical impact of a conviction without altering the formal verdict.

Common questions about criminal defence in Turkey

Can a foreign national file a criminal appeal from outside Turkey?

Yes. The petition is filed by counsel of record on behalf of the defendant and physical presence in Turkey is not required for filing. Appearance may be required at certain hearings — particularly İstinaf hearings where new evidence is taken. Non-resident defendants must remain in close coordination with counsel to authorise procedural decisions in real time.

What happens to my sentence while the appeal is pending?

A timely İstinaf appeal generally suspends the execution of the sentence, with limited exceptions for catalogue offences and pretrial-detention scenarios. Once the conviction becomes final at the highest accessible domestic tier, execution proceeds — which is why the integrity of the appellate sequence is decisive for liberty and asset preservation.

Do constitutional and ECHR applications stop enforcement of the sentence?

As a default rule, no. Bireysel başvuru and ECHR proceedings do not have automatic suspensive effect. In specific circumstances the Constitutional Court may issue interim measures (tedbir kararı) to prevent irreparable harm — typically in cases involving deportation, ill-treatment, or imminent destruction of evidence. Strasbourg may issue Rule 39 interim measures on similar grounds.

Can a sentence be increased on appeal?

It can. A non-frivolous appeal grounded in colourable error rarely produces a worse outcome, but the Regional Court of Justice has authority to modify a sentence upward in defined circumstances — typically where the prosecution has cross-appealed. Appellate strategy must therefore weigh the realistic probability of partial relief against the residual risk of an unfavourable modification.

How do I choose between filing only İstinaf and pursuing the full appellate ladder?

This is a strategic decision driven by the specific grounds available, the sentence imposed, the collateral consequences (asset seizures, immigration restrictions, professional licensing), and the client's appetite for protracted proceedings. A senior appellate practitioner will map the probability and remedy at each tier before recommending the path most likely to deliver substantive relief.

Does my foreign citizenship affect my appellate rights in Turkey?

No. Foreign defendants enjoy the same procedural appeal rights as Turkish citizens, including the right to translation, consular notification, and full appellate review. Citizenship does, however, affect collateral matters such as deportation upon completion of sentence, which is why integrated criminal and immigration strategy is essential.

This guide is general information on Turkish law, not legal advice on your own matter. Rules and practice change; check the position before you act.