Pada tahun 2015, Arab Saudi dan negara-negara Arab lainnya melancarkan serangan kepada kelompok pemberontak Houthi yang berada di wilayah kedaulatan Yaman. Serangan tersebut menimbulkan permasalahan-permasalahan yang harus dicari jawabannya melalui penelitian ini. Mengapa Arab Saudi melakukan intervensi militer semacam itu, Bagaimana Pengiriman pasukan bersenjata atau intervensi militer kepada negara lain menurut prinsip non intervensi dan Piagam PBB, dan bagaimana legalitas intervensi militer Arab Saudi dan koalisinya di Yaman menurut prinsip non intervensi dan Piagam PBB. Penelitian ini akan menjawab 3 (tiga) pertanyaan atau permasalahan di atas. Tindakan Arab Saudi dan koalisinya yang melancarkan serangan militer ke wilayah Yaman pada dasarnya merupakan penggunaan kekerasan dan campur tangan terhadap urusan domestik atau dalam negeri dari Yaman. Campur tangan atau intervensi semacam ini melanggar Pasal 2 (4) dan 2 (7) Piagam PBB yang mengandung prinsip non intervensi. Namun, pelarangan campur tangan atau intervensi khususnya intervensi militer bukan pelarangan yang mutlak. Piagam PBB sendiri memberikan pengecualian terhadap dua pasal pelarangan intervensi tersebut sehingga negara dapat melakukan intervensi khususnya intervensi militer. Intervensi-intervensi yang dikecualikan tersebut ialah intervensi atas mandat Dewan Keamanan PBB dan intervensi atas dasar self-defence. Intervensi militer Arab Saudi dan koalisinya di Yaman merupakan intervensi atas dasar self-defence yang telah memenuhi persyaratan-persyaratannya menurut Piagam PBB.

On 2015, Saudi Arabia Led-Coalition launched a military operation targeted to Houthi Rebel in Yemen. The operation problems that the author of this paper must seek the answers in this paper. Why did the Saudi Led-Coalition launch a military operation in Yemen?, How is the legality of sending an armed force to another state according to the principle of non intervention and the UN Charter?, and How is the legality of military intervention done by Saudi Led-Coalition  in Yemen according to the principle of non intervention and the UN Charter?.This paper will seek the answers of those three problems. That Saudi and its coalition launched a military operation in Yemen is a use of force and an interference against the domestic affair of Yemen. This kind of interference is a violation to article 2 (4) and 2(7) of UN Charter. However, the Charter itself constitutes articles that could be a discretion to intervention prohibition in the Charter. The Charter allows states to counduct two kinds of intervention . Those are intervention under the authorization of the Security Council and intervention based on the right of self-defence. The act that Saudi and its coalition did in Yemen is based on the right of self-defence and they have fulfilled the conditions governed in the Charter.