Yes, ad blockers are legal in the Czech Republic, but their use is constrained by intellectual property, unfair competition, and data protection laws. While no statute explicitly bans ad blockers, courts and regulators—particularly the Office for Personal Data Protection (ÚOOÚ) and the Czech Competition Authority (ČOI)—have scrutinized their deployment in contexts violating copyright or circumventing contractual terms. The 2026 amendment to the Act on Electronic Communications (ZEK) introduces stricter transparency obligations for intermediaries, indirectly impacting ad-blocking practices.
Key Regulations for Ad Blockers in Czech Republic
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Copyright Infringement Risks: Under the Copyright Act (No. 121/2000 Sb.), ad blockers that modify or block copyrighted content (e.g., embedded ads) may constitute circumvention of technical protection measures, triggering liability under § 47a. Courts have ruled against tools facilitating unauthorized access to paywalled or licensed media.
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Unfair Competition Provisions: The Act on Unfair Competition (No. 40/2008 Sb.) prohibits tools that distort market competition by disabling revenue-generating mechanisms for publishers. The ČOI has fined entities distributing ad blockers that undermine publisher-approved monetization strategies, citing § 29(1)(g).
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Data Protection Compliance: Ad blockers collecting or processing user data must adhere to the General Data Protection Regulation (GDPR) and the Act on Personal Data Processing (No. 110/2019 Sb.). The ÚOOÚ has issued guidance warning against blockers that exfiltrate tracking data without consent, classifying such actions as unauthorized processing under Art. 6 GDPR.