Res communis is a concept or doctrine. The expression is a Latin term derived from Roman law that preceded today's concepts of the commons and common heritage of mankind. It has relevance in international law and common law.
In sixth century C.E., the Institutes of Justinian codified the relevant Roman law as: “By the law of nature these things are common to mankind - the air, running water, the sea, and consequently the shores of the sea.” 
'Res communis' has gained new currency in environmental law, in terms of managing natural resources. The key concept is that the state is the trustee of communal natural resources and cannot alienate them into private ownership. Examples are Lake Michigan, Victoria Harbour in Hong Kong  and Sydney Harbour.
Biological examples of res communis include fish and mammals in high seas. Rules for use of the continent Antarctica were based on res communis as was development of space law.
- ^ Wang. Handbook on Ocean Politics & Law. Greenwood Press. 1992. p 64.
- ^ Johnston. The International Law of Fisheries. 1987. p 309.
- ^ Baslar, Kemal (1997). The Concept of the Common Heritage of Mankind in International Law. Brill. ISBN 9789041105059. Retrieved 25 March 2014.
- ^ Barresi, Paul (2012). "MOBILIZING THE PUBLIC TRUST DOCTRINE IN SUPPORT OF PUBLICLY OWNED FORESTS AS CARBON DIOXIDE SINKS IN INDIA AND THE UNITED STATES" (PDF). Colorado Journal of International Environmental Law and Policy. 23 (1): 47. Retrieved 25 March 2014.
- ^ Illinois Central Railroad v Illinois 146 US 387 (1892)
- ^ Society for the Protection of the Harbour Ltd v Town Planning Board  2 HKLRD 787
- ^ Stannards Marine Pty Ltd v North Sydney Council  NSWLEC 99
- ^ Milun, Kathryn (2010). The Political Uncommons: The Cross-cultural Logic of the Global Commons. Ashgate. p. 58. ISBN 978-0-7546-7139-8. Retrieved 25 March 2014.
- ^ Joyner, Christopher (1992). Antarctica and the Law of the Sea. p. 90. ISBN 0792318234. Retrieved 25 March 2014.
- ^ Slomanson, William (2010). Fundamental Perspectives on International Law. p. 288. ISBN 978-0495797197. Retrieved 25 March 2014.