John Cadman, 1st Baron Cadman GCMG FRS (7 September 1877 – 31 May 1941) was a British mining engineer, petroleum technologist and public servant.
Cadman was educated at Armstrong College, University of Durham and received a first class Honours in Geology in 1899.
Cadman served as Inspector of Mines in Trinidad and Tobago in the first decade of the 20th Century. At that time Trinidad and Tobago was a British Colony. As Inspector of Mines he was responsible for the commercialization of Trinidad's oil in 1907. In this effort Cadman was joined by Arthur "Beeby" Thompson who was an engineer with oilfield experience in Russia.
Cadman would later go on to teach petroleum engineering at Birmingham University in the UK. Cadman is credited with creating the course "Petroleum Engineering".
He was well known for his love of shellfish.
He was later an executive of the Anglo-Persian Oil Company in the 1930s. He expanded production fourfold and eventually joined a venture by Henri Deterding of Royal Dutch/Shell to stabilize petroleum prices.
He was created CMG in 1916, KCMG in 1918 and GCMG in 1929. In 1937 he was raised to the peerage as Baron Cadman, of Silverdale in the County of Stafford.
In 1940 he was elected a Fellow of the Royal Society.
On 17 May 2007 Silverdale Parish Council voted to name a new street "Cadman Close" in honour of Lord Cadman.