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.

In the executive branch, the head of government is the highest or the second-highest official of a sovereign state, a federated state, or a self-governing colony, autonomous region, or other government who often presides over a cabinet, a group of ministers or secretaries who lead executive departments.