Dirk Nak (1884 or 1885 – 2 May 1967) was a Dutch trade union leader, active in Denmark.
Born in the Netherlands, Nak became a cigar maker.
In 1913, he moved to Denmark, where he carried on in the same trade, joining the Danish Tobacco Workers' Union.
He stood down from the international in 1952, but held the other positions until his retirement in 1955.
He was also active in the Social Democrats, and from 1945 to 1958 sat on the Copenhagen City Council.