The Finnish Federation of Trade Unions (, SAK) was a national trade union centre in Finland.
The federation was established in 1930, after the Finnish Trade Union Federation (SAJ) was banned. Its initial affiliates were unions which supported the Social Democratic Party of Finland, whereas the SAJ had been dominated by communists. Over time, the communists became prominent in the SAK, and this led a group of unions to split away in 1960 and form a new Finnish Trade Union Federation (SAJ). In 1969, the SAK merged with the new SAJ, to form the Central Organisation of Finnish Trade Unions.