Gille dynasty was a powerful royal house or dynasty which ruled the Kingdom of Norway during the 12th century. It is very unlikely that the rulers ever referred to the Gille dynasty which is a term created by modern historians. The term "Gille" is probably derived from the Middle Irish Gaelic Gilla Críst, i.e. servant of Christ.
King Harald IV of Norway started the Gille (or Gylle dynasty), a putative cadet branch of the Hardrada dynasty (and by extension the Fairhair) dynasty. Harald Gille arrived in Norway from Ireland or the Hebrides and claimed to be the natural son of King Magnus Barefoot whose reign was marked by aggressive military campaigns and conquest, particularly in the Norse-dominated parts of the British Isles. From historical sources, his claim seems to have been based largely upon stories told by his mother and her family during his youth.   
Approximately from the accession of Harald to the throne, the Norwegian civil war period (Borgerkrigstida) started lasting from 1130 to 1240. His descendants would expand the influence, wealth and power of the dynasty.  The royal house replaced the Hardrada dynasty in 1135, and was again replaced scion of Hardrada dynasty in 1162. The line was briefly restored under Inge II Baardson, a cognatic descendant of the dynasty, but was replaced again by the House of Sverre in 1217. 
The rulers within the royal house would often have a rival who opposed the established king's right to rule the realm and dominions. Here is a list of the rulers during the period the house held the power in Norway: