Serangan terorisme pada peristiwa 9/11 merupakan momentum yang memicu dunia internasional untuk memberikan perhatian khusus terhadap isu terorisme. Tak terkecuali NATO sebagai aliansi keamanan yang salah satu negara anggotanya menjadi korban pada serangan tersebut. Operasi Active Endeavour sebagai operasi militer berbasis keamanan maritim digelar demi mencegah aktivitas yang terafiliasi dengan jaringan terorisme internasional. Penelitian ini dimaksudkan untuk mengidentifikasi kepentingan North Atlantic Treaty Organization (NATO) di balik operasi militer Active Endeavour dalam rangka War on Terror 2001-2016. Teori Realisme menyatakan bahwa setiap negara cenderung mementingkan kepentingan nasionalnya dan institusi internasional hanyalah sebuah instrumen negara. Penelitian ini dilaksanakan menggunakan metode sejarah dan menyampaikan data melalui studi kepustakaan dan kajian sejarah. Analisis disajikan melalui beberapa kategori dalam subjudul pembahasan penelitian yang merupakan jawaban dari ketiga rumusan rumusan masalah dalam penelitian ini. Pengamatan yang dilakukan menunjukan keamanan maritim di wilayah laut Mediterania menjadi fokus utama NATO dalam pelaksanaan operasi militer Active Endeavour mengingat kepentingan aliansi baik eksplisit maupun implisit berhadapan dengan besarnya potensi ancaman terorisme di wilayah tersebut. Melalui berbagai gugus tugas yang terdiri dari berbagai armada tempur Angkatan Laut, operasi Active Endeavour memberikan dampak yang signifikan terhadap perkembangan keamanan maritim di wilayah cakupan operasi yaitu laut Mediterania. / The terrorist attack on 9/11 was a momentum that pushed the international community to pay special attention to the issue of terrorism. No exception NATO as a security alliance in which one of its member countries became victims of the attack. Operations Active Endeavour as maritime security-based military operations for the sake of safety affiliated with international terrorism networks. This research was conducted in order to find out the interests of the North Atlantic Treaty Organization (NATO) behind military operations Active Endeavour in the framework of the War on Terror 2001-2016. The theory of Realism states that each country attaches importance to its national interests and international institution is just a state instruments to reach their national interest. This research was conducted using the historical method and submitted data through literature studies and historical studies. The analysis is presented through several categories in the review of the research discussion which is the answer to the research question in this study. Observations made indicate maritime security in the Mediterranean sea region is the main focus of NATO in the implementation of operations Active Endeavour considering the interests of alliances both explicitly and implicitly facing the potential danger of terrorism in the region. Through various task forces consisting of various Navy combat fleets, Active Endeavor operations have a significant influence on the development of maritime security in the area of operation of the Mediterranean sea operations.