Joseph Luns, Dutch politician and diplomat, 5th Secretary General of NATO (died 2002)

Joseph Marie Antoine Hubert Luns was a Dutch politician of the defunct Catholic People's Party (KVP), now merged into the Christian Democratic Appeal (CDA), diplomat, and jurist. He is the longest serving Secretary General of NATO, having served in the position from 1 October 1971 until 25 June 1984.

The secretary general of NATO is the chief civil servant of the North Atlantic Treaty Organization (NATO), an intergovernmental military alliance with 32 member states. The officeholder is an international diplomat responsible for coordinating the workings of the alliance, leading NATO's international staff, chairing the meetings of the North Atlantic Council and most major committees of the alliance, with the notable exception of the NATO Military Committee, as well as acting as NATO's spokesperson. The secretary general does not have a military command role; political, military and strategic decisions ultimately rest with the member states. Together with the chair of the NATO Military Committee and the supreme allied commander, the officeholder is one of the foremost officials of NATO.