The Cabinet Office is a government department in the Empire of Adammia intended to assist the Prime Minister, Deputy Prime Minister and the Cabinet in their duties, as well as organise collaborative efforts between other departments. It is also responsible for any executive government business not covered by other departments, such as tourism and crisis response.

The head of the Cabinet Office is the Prime Minister, however, it is not classed as a Ministry like the other standard government departments and the Prime Minister is not considered the "Minister of the Cabinet Office". The most senior civil servant at the Cabinet Office is the Cabinet Secretary, an official appointed by the Prime Minister with the approval of the Lord/Lady Chancellor. The Cabinet Secretary is the second-highest-ranking civil servant in the Imperial Civil Service. They have the ability to chair meetings of the Cabinet with the Prime Minister's permission. The role of the Cabinet Secretary with regards to the Cabinet is similar to that of the Lord Chancellor with regards to the Ruling Council, and both posts are currently held by Emperor Adam I. As there are very few civil servants outside of the government agencies, the Cabinet Secretary will assist all members of the Cabinet, acting as an informal secretary to all the main ministries. A number of key civil service positions, such as the Attorney General and the Director of Events, formally come under the purview of the Cabinet Office.

The Cabinet Office was established by the Imperial Government Act 2015 on 7 November 2015. The former "Government Headquarters" in the dining room of White Gold Palace, Imperial City became the physical location of the Cabinet Office.