Sir Gilbert Nicholson Flemming, KCB (1897 – 24 October 1981) was an English civil servant.
The son of Percy Flemming, the ophthalmologist, he served in First World War and then attended Trinity College, Oxford.
He did not graduate and entered the civil service in 1921 as an official in the Board of Education.
Subsequently, he was responsible for teacher training generally, including the implementation of the McNair Committee's recommendations.
After retiring, he chaired the governing body of the National College of Agricultural Engineering from 1960, chaired a commission into civil service salaries in East Africa in 1960 and led an inquiry into the grading of the Clerk of the House of Commons's department in 1961.