John Walter Gregory, FRS, FRSE, FGS (27 January 1864 – 2 June 1932) was a British geologist and explorer, known principally for his work on glacial geology and on the geography and geology of Australia and East Africa.
He [John Walter Gregory] visited central Kenya in 1893 and again in 1919 and his 1896 book The Great Rift Valley is considered a classic.