Abstrak Penelitian ini bertujuan untuk menganalisis secara yuridis efektivitas regulasi e-commerce dalam mencegah dan menanggulangi penjualan buku bajakan, serta mengidentifikasi kelemahan substantif dan tantangan dalam implementasi regulasi tersebut. Penelitian ini menguji kesenjangan antara hukum dalam teks (law in books) dan hukum dalam praktik (law in action) terkait perlindungan Hak Cipta di ruang digital. Metode penelitian yang digunakan adalah yuridis normatif dengan pendekatan kualitatif. Teknik pengumpulan data dilakukan melalui studi kepustakaan dan studi dokumen hukum terhadap bahan hukum primer seperti Undang-Undang No. 28 Tahun 2014 tentang Hak Cipta, Undang-Undang No. 7 Tahun 2014 tentang Perdagangan, dan Undang-Undang No. 1 Tahun 2024 tentang ITE, serta berbagai peraturan pelaksananya. Analisis data difokuskan pada evaluasi konsistensi, implementasi, dan kelemahan regulasi yang ada, dengan dukungan data sekunder dari jurnal, artikel, dan studi kasus aktual seperti kasus pembajakan buku milik Devina Hermawan dan Rintik Sendu. Hasil penelitian menunjukkan bahwa meskipun Indonesia telah memiliki kerangka hukum yang relatif lengkap, implementasi regulasi e-commerce belum optimal. Regulasi yang berkaitan dengan penanggulangan penjualan buku bajakan masih tersebar dalam beberapa aturan berbeda sehingga menyulitkan dalam proses penegakan, bersifat reaktif, dan lebih mengandalkan mekanisme notice and takedown yang terbukti lambat dan rumit. Platform e-commerce belum sepenuhnya melaksanakan kewajiban verifikasi proaktif dan pengawasan aktif terhadap produk yang dijual. Selain itu, koordinasi antarlembaga terkait masih lemah, teknologi pendeteksian buku bajakan belum maksimal, serta kesadaran hukum masyarakat masih rendah. Kesimpulan penelitian ini menggarisbawahi bahwa efektivitas regulasi e-commerce dalam menanggulangi penjualan buku bajakan sangat bergantung pada harmonisasi regulasi, penegakan hukum yang konsisten, peningkatan peran pengawasan platform, serta peningkatan literasi hukum masyarakat. (Kata kunci: Buku Bajakan, E-commerce, Hak Cipta, Implementasi, Perlindungan Hukum, Regulasi) Abstract This study aims to analyze, from a juridical perspective, the effectiveness of e-commerce regulations in preventing and combating the sale of pirated books, as well as to identify substantive weaknesses and challenges in the implementation of these regulations. The study examines the gap between the law in books and the law in practice regarding copyright protection in the digital realm. The research method used is normative juridical with a qualitative approach. Data collection was carried out through literature review and legal document studies on primary legal materials such as Law No. 28 of 2014 on Copyright, Law No. 7 of 2014 on Trade, and Law No. 1 of 2024 on Electronic Information and Transactions (ITE), along with various implementing regulations. Data analysis focused on evaluating the consistency, implementation, and weaknesses of existing regulations, supported by secondary data from journals, articles, and actual case studies, such as the book piracy cases involving Devina Hermawan and Rintik Sendu. Research findings indicate that although Indonesia has a relatively comprehensive legal framework, the implementation of e-commerce regulations remains suboptimal. Regulations related to combating the sale of pirated books are still scattered across various different rules, making enforcement difficult; they are reactive in nature and rely heavily on notice-and-takedown mechanisms, which have proven to be slow and cumbersome. E-commerce platforms have not fully implemented their obligations for proactive verification and active monitoring of products sold. Additionally, coordination among relevant agencies remains weak, technology for detecting pirated books is not yet fully utilized, and public legal awareness remains low. The conclusion of this study underscores that the effectiveness of e-commerce regulations in combating the sale of pirated books is highly dependent on regulatory harmonization, consistent law enforcement, an enhanced supervisory role for platforms, and improved public legal literacy. (Keywords: Copyright, E-commerce, Implementation, Legal Protection, Pirated Books, Regulation)