Learn how workplace investigations work in Turkey, including internal procedures, employee interviews, digital evidence, KVKK compliance, disciplinary measures, dismissal risks, and labor-court exposure.
Introduction
Workplace investigations in Turkey are not governed by one standalone “workplace investigations law.” Instead, internal investigations are built from a combination of Labor Law No. 4857, Law No. 6698 on the Protection of Personal Data (KVKK), and Labor Courts Law No. 7036. In practical terms, this means a Turkish employer investigating misconduct, harassment, data leakage, fraud, absenteeism, policy violations, or safety breaches must think about at least four issues at once: whether the investigation is procedurally fair, whether evidence is collected lawfully, whether employee data are processed in compliance with KVKK, and whether any disciplinary or dismissal outcome can survive mediation or court review later.
This legal structure matters because employers often make one of two mistakes. Some act too informally and treat an investigation as a purely managerial process. Others act too aggressively and collect evidence or impose sanctions as if any internal suspicion automatically justifies intrusive monitoring or immediate dismissal. Turkish law supports neither extreme. It gives employers room to investigate, but it also imposes limits through dismissal procedure, data protection, personnel-file duties, and judicial review.
A well-run workplace investigation in Turkey is therefore less about secrecy or speed alone and more about legal architecture. The employer should know what is being investigated, why the evidence is being collected, which legal basis supports each processing activity, who is authorized to review the data, whether the employee must be asked for a defense, whether special-category data are involved, and whether the final action fits Article 18, Article 19, Article 25, or Article 38 of the Labor Law.
This article explains Workplace Investigations in Turkey: Internal Procedures, Evidence, and Legal Risks in a practical, SEO-friendly format. It focuses on the legal foundations of internal investigations, investigation planning, witness interviews, documentary and digital evidence, employee monitoring, corporate email review, biometric and special-category data, disciplinary measures, dismissal procedure, timing rules, mandatory mediation, and the most common employer mistakes that turn an internal process into a labor dispute.
1. The legal foundation of internal workplace investigations
There is no single article in Turkish law titled “workplace investigation.” The legal basis is assembled from several statutory duties. Under Article 75 of Labor Law No. 4857, the employer must create a personnel file for each employee, keep the documents and records required by law, present them to competent authorities when requested, use employee information lawfully and in line with good faith, and avoid disclosing information in which the employee has a legitimate confidentiality interest. That provision is one of the clearest statutory anchors for investigation-related recordkeeping and confidentiality.
At the same time, workplace investigations often lead toward conduct-based discipline or dismissal. That brings in Article 19, which requires written termination notices and says that an indefinite-term contract cannot be terminated for reasons related to the employee’s conduct or performance without first obtaining the employee’s defense, while preserving the employer’s Article 25/II right in properly grounded misconduct cases. It also brings in Article 20, which allows the employee to challenge the dismissal by applying to mediation within one month if the stated reason was not valid.
This means an internal investigation is not legally neutral. From the moment the employer begins gathering facts, the case may already be moving toward a disciplinary warning, wage deduction, termination for valid reason, immediate termination for just cause, or no sanction at all. The legal framework therefore rewards employers who investigate with the likely end-stage in mind.
2. When should an employer launch a workplace investigation?
A Turkish employer should generally consider a formal internal investigation when the alleged conduct may affect workplace discipline, contractual compliance, occupational safety, confidentiality, data protection, or possible dismissal grounds. The most obvious statutory triggers are found in Article 25, which lists the employer’s just-cause termination grounds, including deception at hiring, insults, sexual harassment, assault, intoxication, trust abuse, theft, disclosure of trade secrets, unauthorized absenteeism, persistent refusal to perform duties despite reminder, and endangering workplace safety or causing substantial damage.
But not every internal issue belongs in an Article 25/II file. Some matters relate only to ordinary conduct or performance problems and should be handled under the valid-reason framework of Article 18, not through immediate dismissal. Article 18 requires a valid reason for dismissing eligible indefinite-term employees and also lists reasons that cannot constitute valid grounds, including union activity, administrative or judicial complaints made to pursue rights or fulfil obligations, and discrimination-related reasons such as race, sex, family responsibilities, pregnancy, and similar causes. That matters because an employer who opens an investigation after a complaint or protected activity must be careful not to convert a compliance response into retaliatory dismissal risk.
In practice, the safest trigger question is not simply “did something go wrong?” but “what legal consequence might follow if the allegation is true?” If the answer may involve discipline, wage deduction, suspension of access, reporting to authorities, or dismissal, a structured investigation process is usually much safer than ad hoc managerial action.
3. Start with a defined scope and lawful purpose
Under Article 4 of KVKK, personal data must be processed lawfully and fairly, for specific, explicit, and legitimate purposes, in a manner limited and proportionate to those purposes, and retained only as long as necessary. That means an investigation should begin with a defined scope: what allegation is being examined, which data are relevant, who will review them, and what outcome the employer is trying to reach. Employers that investigate too broadly often create their own KVKK problem even before reaching any labor-law outcome.
This principle is especially important in HR because investigations often tempt employers to “look at everything.” Turkish data protection law pushes in the opposite direction. The employer should identify a concrete allegation, narrow the evidence set to that allegation, and avoid processing unrelated employee data merely because the systems are available. In workplace investigations, proportionality is not a theoretical concept; it is one of the main legal limits on internal evidence gathering.
As a practical compliance step, employers should usually create an internal investigation memorandum or case-opening note identifying the purpose, legal basis, source of allegation, persons involved, and expected evidence categories. Turkish law does not require that exact document by name, but Article 75’s recordkeeping logic and KVKK’s purpose-limitation framework strongly support that structured approach.
4. Choosing the right lawful basis under KVKK
The most common HR privacy mistake in investigations is overreliance on explicit consent. Under Article 5 of KVKK, personal data may be processed without consent where a lawful basis exists, including where processing is expressly provided by law, necessary for contract performance, necessary to comply with a legal obligation, necessary for the establishment, exercise, or protection of a right, or necessary for the controller’s legitimate interests provided fundamental rights and freedoms are not harmed. KVKK’s own guidance states that if a processing activity can already be based on a lawful basis other than consent, obtaining additional explicit consent is not the correct approach.
That rule matters directly for investigations. Many internal investigation steps—reviewing employment records, collecting witness statements, examining access logs, or preserving relevant business correspondence—are more naturally based on the employer’s legitimate interests, contractual relationship, legal obligations, or the need to establish, exercise, or protect a right than on consent. In fact, relying on consent in an investigation can be unstable because the employment relationship often involves an imbalance and the investigation may continue even if the employee later tries to withdraw consent.
Board practice supports this. In Decision 2023/86, the Board summary reflects the employer’s position that review of the employee’s corporate email account was based on Article 5(2)(e) and Article 5(2)(f)—protection of a right and legitimate interest—rather than explicit consent, in a context involving suspected disclosure of company information and compliance with internal email policies. That does not mean every employer email review is lawful, but it does show the correct analysis starts with the lawful-basis framework rather than a generic consent form.
5. Employee notice and transparency cannot be skipped
Even where a lawful basis exists, Article 10 of KVKK still requires the employer to inform the employee. KVKK’s official notice guide states that the obligation to inform is independent of whether explicit consent or another lawful basis exists, and that the burden of proving the notice was given lies with the data controller. The guide also stresses that notice must comply with the Article 4 principles and that consent and notice should be handled separately.
This point becomes critical in workplace investigations involving digital systems. If an employer wants to rely on corporate email review, device review, log analysis, or camera footage during an investigation, prior notice about those systems and purposes becomes one of the key legal safeguards. The absence of notice weakens the employer’s position significantly, especially where the employee later complains that monitoring was unexpected or excessive.
The safest employer practice is therefore to build investigation readiness into pre-existing HR and IT policies. Corporate email, device use, monitoring, acceptable use, security review, and disciplinary investigation policies should explain what business systems may be reviewed, for what purposes, under which conditions, and by whom. Turkish law does not require one single master policy, but KVKK’s notice obligations and Board practice make prior transparency extremely important.
6. Witness interviews and employee statements
Employee interviews are often the core of a workplace investigation, yet Turkish law does not create a single formal interview code. Instead, the procedural importance of employee statements comes from dismissal law and proof risk. Article 19 says that an indefinite-term contract cannot be terminated for conduct or performance reasons without taking the employee’s defense, except where the employer relies on a properly grounded Article 25/II immediate-termination case. Even then, because the employer bears litigation risk if the justification later fails, obtaining statements and documenting the factual sequence is usually prudent.
This means interviews should not be treated as casual conversations. The employer should identify who is interviewed, why, on what date, whether the statement is complaint-based, witness-based, or defense-based, and whether the employee is being asked about conduct that may later be used for discipline or dismissal. If the matter may lead to a conduct- or performance-based termination outside Article 25/II, the defense-taking requirement becomes even more important.
From a practical perspective, the safest interview model usually includes a written record, a defined allegation, neutral questions, separation between fact-gathering and decision-making, and careful handling of private or irrelevant information. The goal is not only to learn what happened, but also to create a record that can later be defended under both labor law and KVKK.
7. Reviewing corporate emails and digital communications
Corporate email review is one of the most sensitive investigation tools in Turkey. The Board’s summaries in 2021/1187 and 2023/86 show that workplace email access is examined through a combination of purpose, prior notice, legitimate interest, and proportionality. In the 2023/86 summary, the employer argued that corporate email accounts could be monitored for security, detection of personal use outside business purpose, investigation of suspected misconduct, prevention or detection of unlawful acts, and confirmation of compliance with workplace rules, and that employees had been informed through policies and notices.
By contrast, the 2021/1187 summary involved a complaint by a former employee whose corporate email account was accessed without notice, and whose private correspondence and banking information appeared in litigation materials. This illustrates the legal risk clearly: even where the employer sees a business need, unannounced or overly broad access to an employee’s corporate mailbox may create a KVKK exposure, especially when personal content is swept into the review.
The practical lesson is that corporate email review in Turkish workplace investigations should follow a narrow, suspicion-based, documented model. Employers should review the least intrusive evidence first, limit mailbox access to the investigation purpose, avoid unnecessary reading of clearly personal content, and make sure prior internal policies and notices support the monitoring activity. Turkish law does not prohibit workplace email review outright, but it strongly disfavors surprise, overbreadth, and weak documentation.
8. Biometric data, fingerprints, and high-risk investigation tools
Biometric data are especially sensitive in workplace investigations. Article 6 of KVKK classifies biometric data as special-category data, and KVKK’s 2025 guide on special-category data explains that the 2024 reform kept biometric data within the special-category regime while creating updated lawful bases. The guide also gives fingerprint access systems as an example of biometric processing.
Board Decision 2020/404 is particularly instructive. The summary states that all employees’ fingerprints were collected, employees were effectively forced to provide them, no adequate notice was given, and the employer argued the fingerprints were used for emergency management, physical security, and similar aims. The Board summary also states that biometric data do not lose their biometric character merely because they are hashed, and that using fingerprints for physical security was disproportionate where less intrusive alternatives such as magnetic cards, RFID tags, or SMS-based entry could have been used.
For workplace investigations, that means employers should be extremely cautious about using biometric systems as evidence or as investigation tools. If the employer wants to rely on biometric attendance or access records in an investigation, it should first ensure that the underlying biometric system itself was lawfully justified, proportionate, properly notified, and protected by adequate measures. An unlawful biometric system can contaminate the investigation rather than strengthen it.
9. Special-category data in investigations
Investigations may also involve health information, disability information, union membership data, criminal-conviction information, or other special-category data. Under the amended Article 6, these data may be processed without explicit consent only if one of the listed special-category conditions exists, including express legal provision, protection of life or physical integrity, establishment or protection of a right, healthcare-related needs, or necessity for fulfilment of obligations in employment, occupational health and safety, social security, social services, or social assistance. KVKK’s official special-category guide warns that this employment-related ground does not create unlimited room for employers to process all sensitive employee data.
This matters because investigations often involve temptation to gather more sensitive information than necessary. A workplace harassment complaint may contain health records. A workplace violence file may contain criminal or disciplinary history. A substance-abuse allegation may tempt the employer to process medical data without enough legal basis. Turkish law requires the employer to ask not only whether the data are useful, but whether a lawful Article 6 condition exists and whether the processing is proportionate to the investigation purpose.
The safest approach is to separate ordinary and special-category evidence, restrict access more tightly for special-category material, and record the exact legal basis relied upon. Employers should also remember that Article 6 requires the Board’s adequate safeguards for special-category processing, so sensitive investigation files should not circulate casually within management.
10. Data security during the investigation
Article 12 of KVKK requires the data controller to take all necessary technical and organizational measures to prevent unlawful processing, prevent unlawful access, and ensure preservation of personal data. KVKK’s security guide emphasizes that the controller must choose measures appropriate to its risks and systems, and that the controller remains jointly responsible even where another person processes data on its behalf.
In a workplace investigation, that means the evidence file itself becomes a security risk object. Witness statements, email exports, access logs, video captures, HR notes, disciplinary drafts, and legal assessments often contain sensitive personal data. Employers therefore need a controlled-access model: only persons who genuinely need the information should see it, transmission should be limited, and storage should be structured rather than improvised through personal email accounts or uncontrolled messaging groups.
A second security point concerns breaches. Article 12 requires breach notification to the Board and the data subject in the shortest time if processed data are obtained by others unlawfully. In an investigations context, that means leak of an investigation file can itself create a second legal problem on top of the original misconduct issue. An employer should therefore plan investigation-file handling with the same seriousness as payroll, HRIS, or customer-data security.
11. Documentation, personnel files, and retention
Investigations should also be documented in a way that fits Article 75 of Labor Law No. 4857. The employer must keep the records and documents required by law in the personnel file and use employee information lawfully while protecting confidential information in which the employee has a legitimate interest. This makes Article 75 a natural legal home for core investigation documents, at least where they relate directly to the employee’s employment relationship.
But documentation does not mean indefinite storage. Under Article 7 of KVKK, personal data must be erased, destroyed, or anonymized when the reasons requiring their processing no longer exist. KVKK’s erasure and destruction framework and guidance make clear that the controller must act ex officio when the retention basis ends, not only when the employee asks. At the same time, Board practice reflected in 2021/1218 indicates that retention of some personnel-file information after termination may be justified where it may be needed in future disputes.
For employers, the practical lesson is to define retention logic at the beginning. Not every interview note, screenshot, draft summary, or duplicated email export should remain in the system forever. Some records may need to move into the personnel file; others may need secure destruction when the investigation closes. A legally defensible workplace investigation is documented, but not hoarded indefinitely.
12. Disciplinary outcomes short of dismissal
Not every investigation must end in dismissal. Some cases lead to warnings, training, policy reminders, access restrictions, or wage-deduction penalties. Where the employer considers a wage-deduction sanction, Article 38 of Labor Law No. 4857 becomes critical. It states that wage-deduction penalties may be imposed only for reasons shown in the collective bargaining agreement or employment contract, the reason must be notified to the employee immediately, and the deduction may not exceed two days’ wages in one month. The deducted sums must also be deposited into the Ministry-designated bank account for workers’ education and social services.
This rule is often overlooked in internal investigations. Employers sometimes conclude that misconduct “deserves a fine” and then offset the amount from payroll directly. Turkish law does not allow that kind of informal penalty system. If a disciplinary wage deduction is contemplated, the contractual or collective basis must exist and Article 38’s limits must be respected.
The practical implication is that investigation outcomes should be matched to the correct legal instrument. A weak case that does not justify dismissal should not be “solved” by an unlawful deduction. Employers should instead select a lawful disciplinary response that fits both the evidence and the statute.
13. Investigations that lead to dismissal
Where the investigation points toward dismissal, the employer must classify the case correctly. If the facts fit Article 25/II—for example theft, trust abuse, disclosure of secrets, harassment, or unauthorized absenteeism in the statutory pattern—the employer may consider immediate termination. But Article 26 imposes a strict timing rule: for morality-and-good-faith grounds under Articles 24 and 25, the right to terminate must be exercised within six working days from learning of the act and, in principle, within one year from the act. This means investigations cannot drift indefinitely if the employer plans to rely on Article 25/II.
If the case does not clearly fit Article 25/II, the employer may instead be in the ordinary conduct or performance sphere governed by Articles 18 and 19. In that setting, the employer must give a written notice, state the reason clearly, and, for conduct or performance dismissals, obtain the employee’s defense first. That is why investigations matter so much: they often determine whether the employer can rely on immediate dismissal or must proceed through the valid-reason framework.
A common employer mistake is to conduct only a shallow investigation and then choose Article 25/II because it appears financially attractive. If the court later finds the facts insufficient, the worker may challenge the dismissal, and the lack of proper investigation often becomes part of the employer’s evidentiary problem. Under Turkish law, the label “just cause” does not save an unsupported dismissal.
14. Court risk, labor courts, and mandatory mediation
Internal workplace investigations often end in external legal disputes. Under Article 5 of Labor Courts Law No. 7036, labor courts hear disputes arising from the employment relationship between workers under the Labor Law or service contracts and employers or employer representatives. Under Article 3, lawsuits involving employee or employer receivables, compensation, and reinstatement claims generally require prior application to mediation, while the worker who challenges a dismissal as invalid must apply to mediation within one month under Article 20 of the Labor Law.
This means an investigation is not just an internal compliance exercise. It is often the evidence base for later mediation and litigation. If the case involves dismissal, the employer should expect the investigation record to be tested by a mediator and, potentially, by the labor court. Weak notice, unclear findings, inconsistent statements, overbroad digital evidence collection, or lack of employee defense may all reduce the employer’s ability to defend the outcome later.
For employers, the practical consequence is simple: investigate as if the file will later be read by a mediator, a judge, and the KVKK Board. In Turkey, it often will be.
15. The most common employer mistakes in workplace investigations
The first common mistake is launching an investigation without a defined scope and then collecting far more data than necessary. That creates Article 4 proportionality risk under KVKK. The second is relying on consent instead of choosing the right lawful basis under Articles 5 and 6. The third is reviewing corporate email or digital systems without strong prior notice and policy infrastructure. The fourth is using biometric systems or other high-risk tools without special-category analysis. The fifth is delaying too long and then trying to use Article 25/II after the Article 26 deadline.
The sixth common mistake is skipping the employee’s defense in cases that actually belong to Article 18 and Article 19 rather than Article 25/II. The seventh is imposing disciplinary wage deductions casually despite Article 38’s limits. The eighth is documenting too little for labor-law purposes or too much for data-minimization purposes. The ninth is allowing the investigation file itself to become a data-security incident because access and storage controls are weak.
The employers who avoid these mistakes usually follow one core principle: they treat workplace investigations as a legally structured process, not as a management reflex.
Conclusion
Workplace investigations in Turkey sit at the intersection of labor law, data protection law, and dispute procedure. There is no single investigation statute, but the legal framework is still clear: the employer must document and handle the process in a way that fits Labor Law No. 4857, especially Articles 18, 19, 20, 25, 26, 38, and 75, while also complying with KVKK, especially Articles 4, 5, 6, 7, 10, 11, and 12. If the investigation leads to dismissal or monetary claims, Law No. 7036 and mandatory mediation rules also become central.
For employers, the strongest investigation model is not the most aggressive one. It is the one that is scoped narrowly, documented clearly, based on the correct lawful basis, respectful of employee privacy, careful with special-category data, timely under Article 26 where relevant, and aligned with the probable disciplinary or dismissal outcome. For employees, the key point is that internal investigations are not law-free spaces. In Turkish law, evidence collection, digital monitoring, defense rights, and dismissal consequences all remain reviewable. A workplace investigation can protect the employer, but only if the investigation itself is conducted lawfully.
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