Application and Proof of Foreign Law in Turkish Courts

1) Why this topic matters in cross-border disputes

In disputes involving a foreign element—international contracts, cross-border family matters, foreign employment relationships, or torts with an international dimension—the “applicable law” often determines the outcome. Limitation periods, heads of damages, interest rules, contractual validity, and even the existence of a claim may change dramatically once a foreign law governs the merits.

That is why applying foreign law and ascertaining its content are two distinct but interconnected tasks. Turkish courts may be required to apply foreign law; however, establishing the precise content of that foreign law is frequently the most demanding part of the litigation strategy.

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2) The core rule in Turkey: the judge applies foreign law ex officio (PILA Art. 2)

Turkish private international law treats foreign law as “law” rather than a mere factual matter that must be pleaded like an allegation. Article 2 of Turkey’s Private International Law and Procedural Law Act (Law No. 5718) provides that:

• The judge applies Turkish conflict-of-laws rules and the foreign law designated by those rules ex officio.
• The judge may request the assistance of the parties in determining the content of the applicable foreign law.
• If the relevant provisions of the foreign law cannot be determined despite all investigations, Turkish law applies.

This framework produces two practical consequences:

1. A court should not disregard foreign law merely because a party failed to “plead” it.
2. In practice, parties must still actively assist the court, because determining foreign law content is rarely straightforward.

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3) Key limits: public policy and overriding mandatory rules

Even where foreign law is applicable, Turkish law recognizes important limits.

• Public policy (ordre public): If a foreign rule that would apply to the case is manifestly contrary to Turkish public policy, it will not be applied; Turkish law may step in if needed.
• Overriding mandatory rules: In certain circumstances, Turkish overriding mandatory provisions apply regardless of the otherwise applicable foreign law.

For practitioners, this means: the “foreign-law package” should include not only the substantive rule but also a short risk analysis on whether public policy or overriding mandatory rules might be triggered.

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4) What does “proof” mean here?

Although foreign law is treated as law and applied ex officio, the content of that law must be reliably established. In Turkish practice, the word “proof” often refers to the process of ascertaining foreign law content—not proving facts.

Courts may need:

• the consolidated statute text (latest amendments),
• effective dates and transitional rules,
• authoritative sources (official gazette / official database),
• sometimes leading case law (where relevant),
• academic commentary or practice guidance,
• certified translations and authenticity elements.

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5) How Turkish courts ascertain foreign law: tools and channels

a) Party assistance and procedural directions
PILA Art. 2 expressly allows the judge to ask parties for assistance in determining foreign law content.
A sound strategy is to address applicable law early, attach foreign-law materials with certified translations, and request a clear procedural roadmap (time to submit materials, specific questions for expert input, etc.).

b) Official channels: Ministry of Justice and the European Convention mechanism
Turkey participates in the Council of Europe framework on obtaining information on foreign law (European Convention on Information on Foreign Law and related instruments).
In practice, the Council of Europe–based mechanism and central authority practice can support courts in requesting foreign law information through official channels. The Turkish Ministry of Justice’s relevant directorate is often referenced in this context.

c) Experts and “technical assistance” (carefully framed)
Under the Code of Civil Procedure, an expert may be appointed for matters requiring special/technical knowledge beyond the judge’s ordinary legal expertise.
Foreign law content is a legal question, but in many cases it demands specialized comparative-law skills, language competence, and access to authoritative materials. Therefore, practitioners typically frame expert involvement not as “legal qualification,” but as technical assistance to identify, verify, and explain the foreign law materials—while the final legal reasoning remains with the judge.

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6) What if foreign law cannot be determined?

PILA Art. 2(2) is a safety valve: if foreign law provisions relevant to the case cannot be determined despite all investigations, Turkish law applies.
However, this is not a shortcut. The file should reflect a genuine investigation effort: party submissions, official requests where appropriate, and a transparent explanation of why the foreign law could not be established.

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7) Supreme Court sensitivity: insufficient investigation may lead to reversal

Recent academic reviews of case law indicate that the Supreme Court has treated “applying Turkish law without sufficiently investigating the applicable foreign law” as a ground for reversal in some scenarios, and has pointed to steps such as granting time to parties and requesting materials through the Ministry of Justice channel.
Practically, this means: a robust investigation record protects both the judgment and the client’s interests.

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8) Practitioner checklist (ready to convert into pleadings)

1. Map the conflict rule: Identify the connecting factor and why it leads to a specific foreign law.
2. Prepare a foreign-law dossier:
   • consolidated statutory provisions,
   • effective dates and amendments,
   • official source references,
   • (if needed) leading case law and short practice notes,
   • certified translations.
3. Request a procedural plan: time for submissions, targeted questions, official request routes (PILA Art. 2 logic).
4. Add a public policy/mandatory rules note: PILA Art. 5–6 risks.
5. Build the “investigation record”: if Art. 2(2) is to be invoked, show the court’s and parties’ efforts clearly.

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Conclusion

In Turkey, foreign law is not an optional add-on; it is often a binding component of the merits analysis. Winning (or safely settling) a cross-border case depends on treating foreign law content as a litigation deliverable: accurate, current, verifiable, translated, and strategically explained. A well-built foreign-law record reduces the risk of delay, reversal, and client harm—and increases predictability in international disputes.