Martis is a comune located in the Metropolitan City of Sassari within the Italian region of Sardinia. It is situated approximately 180 kilometres north of Cagliari and about 25 kilometres east of the city of Sassari.
The municipality covers an area of 22.9 square kilometres and had a recorded population of 608 as of December 31, 2004. Martis shares borders with the municipalities of Chiaramonti, Laerru, Nulvi, and Perfugas.