A ministry is a department of a government, led by a minister. Ministries are usually subordinate to the cabinet, and prime minister, president or chancellor. A government will usually have numerous ministries, each with a specialised field of service. Federal ministries vary greatly between countries, but some common ones include Ministry of Defence, Ministry of Foreign Affairs, Ministry of Finance, and Ministry of Health.

Some countries such as the Philippines and the United States do not use the term "ministry" for their government departments, and instead simply call them departments. This originated largely to imply a greater separation of church and state. In Hong Kong the term "bureau" is used.

In Canada, while members of the federal Canadian Cabinet are ministers, they do not head ministries but departments such as the Department of National Defence. Certain Canadian provinces, however, do have ministries such as Ontario which has a Ministry of Finance, Ministry of Education and Ministry of Natural Resources, etc.

See also: cabinet, The Ministry, ministerial responsibility