Sido Martens (born Leeuwarden, The Netherlands, 1 March 1949) is a folk musician and songwriter from the northern Dutch province of Friesland. Perhaps best known for his work with popular seventies folk group, Fungus (Martens recorded two LPs with Fungus in 1974 and 1975), he released his début solo album, Land Water in 1975 and put out many albums since. Martens sings in Frisian, Dutch and English.

Martens' musical career took off in 1972 when he co-founded Frisian folk outfit, Farmers Union. Before an LP was recorded, Marten was asked to join Fungus, which he did. After his years with Fungus, he regrouped with Farmers Union and finally released an LP with them, entitled Re-Union (1979).

Martens recorded and released five solo albums between 1975 and 1980, then turned his back on music, disappointed and - perhaps - a bit frustrated. He returned in 1996 with the album, De Loper, which marked the start of his 'second career', as he describes it. This 'second career' has yielded well over twenty albums, most of them self-released. 2018 saw the release of two records, Monomaan and SM 2018.

Sido Martens continues to perform around The Netherlands. Read more on Last.fm. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.