The District Officer, was a commissioned officer of one of the colonial governments of the British Empire, from the mid-1930s also a member of the Colonial Service of the United Kingdom, who was responsible for a District of one of the overseas territories of the Empire.

The Colonial Service, also known as His/Her Majesty's Colonial Service and replaced in 1954 by Her Majesty's Overseas Civil Service (HMOCS), was the British government service that administered most of Britain's overseas possessions, under the authority of the Secretary of State for the Colonies and the Colonial Office in London. It did not operate in British India, where the same function was delivered by the Indian Civil Service, nor in the Anglo-Egyptian Sudan, which was administered by the Sudan Political Service, nor in the internally self-governing colony of Southern Rhodesia.