Angterra nullius (pagbigkas: te•ra nul•yus;maramihan:terrae nullius) ay pananalitangLatin na hango saBatas Romano na ibig sabihin ay "lupaing walang nagmamay-ari".[1] Ito'y ginagamit sa pandaigdigang batas upang ilarawan ang teritoryong hindi pa napasasailalim sa soberanya ng alin mang estado, o kung saan ang dating soberano ay nagpahayag o nagpahiwatig ng pagbitaw ng soberanya. Ang soberanya sa teritoryongterra nullius ay maaaring makuha sa pamamagitan ng pag-okupa,[2] gayunman sa ilang kaso, maaari nitong labagin ang pandaidigang batas o tratado.
Even as to terra nullius, like a volcanic island or territory abandoned by its former sovereign, a claimant by right as against all others has more to do than planting a flag or rearing a monument. Since the 19th century the most generous settled view has been that discovery accompanied by symbolic acts give no more than "an inchoate title, an option, as against other states, to consolidate the first steps by proceeding to effective occupation within a reasonable time.8 I. Brownlie, Principles of Public International Law 146 (4th ed.1990); see also 1 C. Hyde, International Law 329 (rev.2d ed.1945); 1 L. Oppenheim International Law §§222-223, pp. 439-441 (H. Lauterpacht 5th ed.1937); Hall A Treatise on International Law, at 102-103; 1 J. Moore, International Law 258 (1906); R. Phillimore, International Law 273 (2d ed. 1871); E. Vattel, Law of Nations, §208, p. 99 (J. Chitty 6th Am. ed. 1844).