The Independent Senate Group (, OSF) is a parliamentary party in the Dutch Senate with one senator, representing several provincial parties. The Dutch Senate is elected by the legislatures of the provinces. In 1995, several provincial parties and the Greens proposed their own list. Marten Bierman, who headed the list, was elected senator. In 1999, Bierman was re-elected. In 2003, Hendrik ten Hoeve became senator for the OSF. He had been member of the Frisian provinciale legislature for the Frisian Nationalist Fryske Nasjonale Partij. He remained senator and leader of the party until 2011, when his role was taken over by Kees de Lange. The main parties involved are the Frisian National Party, The Greens, the Party for the North, the Party New Limburg and the Brabant Party.