Sir Ralph Denham Rayment Moor, KCMG (31 July 1860 – 14 September 1909) was the first high commissioner of the British Southern Nigeria Protectorate.

On 26 October 1882 he entered the Royal Irish Constabulary as a cadet, and becoming in due course a district inspector resigned after involvement in a divorce case on 9 February 1891.

In July 1892 he was appointed by the Foreign Office vice-consul for the Oil Rivers district, and from 6 September 1892 to 15 February 1893 acted as commissioner.

During his years as high commissioner slave trade was abolished in the protectorate, replaced by a growing labour market and cash currency.

He then allied himself with Sir Alfred Lewis Jones; he gave valuable advice on West African affairs, and aided in the development of the British Cotton Growing Association.