Gattaran [gɐˈt:aɾan], officially the Municipality of Gattaran (Ibanag: Ili nat Gattaran; Ilocano: Ili ti Gattaran; Tagalog: Bayan ng Gattaran), is a municipality in the province of Cagayan, Philippines. According to the 2024 census, it has a population of 59,704 people.

The town's historic spots and tourist landmarks include the Lal-lo and Gattaran Shell Middens, Magapit Protected Landscape, Maduppaper Caves, the Mapaso Hot Spring and the Tanglagan Falls whose warm and cold waters meet and flow together on one bed to become the Dummun River. Another attraction of Gattaran is Bolos Point, a wildlife sanctuary.

The town was traditionally known as 'Najiping' (now the barangay of Nassiping). In Fr. Jose Bugarin's Ibanag dictionary (orig. 1600's, but this excerpt taken from Lobato de Santo Tomas version 1854) called it 'Najjiping' from the Ibanag word for 'conjoined, twins'. "Najjiping, town of this province, named so for being where the big river, or Bannag [Cagayan River], and the small [lit. 'chico'] tributary or Itabes (Itawis) river meet."

In the Murillo Velarde Map (1734), towns in the area are identified as "Gatara" and "Nasipin". The name of Gattaran itself is believed to originate from the word gattad which means "mountain-side", a reference to the town being flanked by the Sierra Madre mountains.

In the place where Gattaran lies today were three former ecclesiastical towns: Nassiping, Dummun, and Gattaran proper. Nassiping is the oldest among the three, founded on June 15, 1596, with Santa Catalina as the patron saint; Dummun was founded on May 24, 1598, and Gattaran, May 20, 1623. Since each of these towns had few inhabitants and had only one priest to administer to their religious needs, they were merged for ecclesiastical convenience into one municipality in 1877 by virtue of a Diocesan Order from the Bishop of Nueva Segovia (Lallo). Fray Francisco Suejos, O.P. was the first Gobernadorcillo.

During the Spanish regime, the natives grew spiritually; but with the Americans, they grew educationally and the inhabitants assimilated a more sophisticated lifestyle. During the American period, Gattaran annexed the town of Nassiping, which was reduced into a barrio, in 1906. Under the Commonwealth government, the first Municipal Mayor was Melencio Adviento, who begun the construction of the present municipal building. The building was finished during the term of the next mayor, Atty. Hipolito Mandac. The municipal building was inaugurated in September, 1941. Four months after its inauguration, World War II broke out, the Japanese Forces occupied the town and all records, cadastral titles and others were confiscated by the invading forces. In 1944, the war's escalation led to the town's depopulation, with its inhabitants fleeing to the Sierra Madre or to the Zinundungan Valley in the west, now part of Lasam.

With the coming of the Americans to adding Filipino soldiers under the Philippine Commonwealth Army and Philippine Constabulary, the whole province was liberated from the Japanese forces. The first election of the Republic in 1947 made Delfino Liban the mayor. The administration marked the building of roads in the barrios, improvements of streets and others.

In 1950, the barrios of Gattaran to the west of the Cagayan River was separated to form the town of Lasam.