The prime minister of Japan is the head of government and the highest political position of Japan. The prime minister chairs the Cabinet of Japan and has the ability to select and dismiss its ministers of state. The prime minister also serves as the commander-in-chief of the Japan Self Defence Forces and is a sitting member of either house of the National Diet. The current prime minister is Fumio Kishida of the Liberal Democratic Party, who assumed the office on 4 October 2021.

The Naikaku Sōri Daijin Kantei (内閣総理大臣官邸) or Prime Minister's Office is the official workplace of the Prime Minister of Japan. It is commonly referred to as Shushō Kantei (首相官邸), or simply Kantei (官邸). Unlike many other famous offices or palaces of heads of states, such as the Kremlin in Russia or the White House in the United States, the Japanese Prime Minister's Office has no nickname. Naikaku Sōri Daijin Kantei literally translates to "Prime Minister's Office" in English.