John Johnston O'Neill (November 12, 1886 – June 1, 1966) was a Canadian geologist and academic.
Born in Port Colborne, Ontario, the son of Thomas John O'Neill, an Irish immigrant, and Mary Jane Henderson, O'Neill received a Bachelor of Science and Master of Science degrees in geology and mining from McGill University in 1909 and 1910.
In 1913, he spent a year as a geologist on Vilhjalmur Stefansson's Canadian Arctic Expedition.
He was a founder, governor, and board chairman of the Arctic Institute of North America.
[2] In 1999 a new mineral from Mont Saint-Hilaire was named "oneillite" in his honour.