Masfjorden is a municipality in the county of Hordaland, Norway. Masfjorden was separated from Lindås on 1 March 1879.
The municipality is located around the fjord which is also called the Masfjorden which almost divides the municipality completely into a north side and a south side. A cable ferry connects these two parts. This is the only cable ferry in Norway that transports vehicles. The main population centre is located at Nordbygda on the north side. The local council however is located on the south side.
The Old Norse form of the name was Matrsfjǫrðr. The first element is the genitive case of the old (uncompounded) name of the fjord: Matr. This name is derived from matr m which means "food" - and the meaning is "the one full of food (fish)".
The coat-of-arms is from modern times. They were granted on 28 September 1990. The arms feature three heldrer, a traditional tool made of wood for fastening a rope around a load. They are meant to symbolize unity. Three of these objects appear in yellow and they are centered on a field of red.