William Gregor (25 December 1761 – 11 June 1817) was a British clergyman and mineralogist who discovered the elemental metal Titanium.

[2] He was educated at Bristol Grammar School, where he became interested in chemistry, then after two years with a private tutor entered St John's College, Cambridge, graduating BA in 1784 and MA in 1787.

Here he continued his remarkably accurate chemical analysis of minerals, most of which came from Cornwall, such as the zeolites found in gabbro on The Lizard.

But he is best known for one of his earliest discoveries: in 1791, while analysing the minerals in a black sand he had discovered in the Manaccan valley, he isolated the calx of an unknown metal which he named manaccanite.

Never letting his scientific work interfere with his pastoral duties, he was also a distinguished landscape painter, etcher and musician.