Matthew Locke (fl. 1660–1683) was an English administrator, holder of the post of Secretary at War from 1666 to 1683, when he sold it. Locke was clerk to the "Irish and Scottish Committee" set up in 1651, and later gave evidence against Henry Vane the Younger who was on it. He was a nephew of Sir Paul Davis, also concerned in Irish business as administrator, and was then private secretary to George Monck. He was related also, at some distance, to Robert Southwell. The secretaryship was bought from Locke in 1683 by William Blathwayt, who had royal backing.