William Ramsay (Glasgow, October 2nd 1852 - High Wycombe, July 13rd 1916) was a British Chimiste . He was the nephew of the geologist Sir Andrew Ramsay.

Its principal discoveries were made in inorganic chemistry. For the period 1885 - 1890, it published many articles on nitrogen oxides, then it made the discovery of the Argon, of the Hélium, the Néon, the Krypton and the Xénon. He was prize winner of the Davy Médaille in 1895.

In 1894, Ramsay attended a conference of Lord Rayleigh, who had noted a difference between the densities of nitrogen made by the chemical decomposition of ammonia, and nitrogen isolated from the air after having removed the other known components (oxygen, carbon dioxide, steam).

Ramsay suggested that this atmospheric nitrogen can contain another element. For this showing it passed nitrogen isolated from the air above hot magnesium to make it react in solid Mg₃N₂. After this reaction was complete, there remained still another gas which was completely inert and could react with no other element. Ramsay named this new element argon (Greek: inactive).

Sir William Ramsay accepted the Nobel Prize of chemistry, in 1904, for its discovery of the chemical elements of the series of the rare gases in the air. In the same year his/her collaborator Lord Rayleigh accepted the Nobel Prize of physics for the discovery of argon.

He died in High Wycombe, in the Buckinghamshire (England).