Overhalla is a municipality in Trøndelag county, Norway. It is part of the Namdalen region. The administrative centre of the municipality is the village of Ranemsletta (also called Overhalla). Other villages include Melen, Hunn, Skogmo, Svalia, and Øysletta.

The population is concentrated in the relatively broad Namsen river valley at the center. Public services, agriculture, and tourism are the main sources of income. Overhallahus (a house building company) and Pharmaq (a fish vaccine factory) are both located in the municipality.

The 730-square-kilometre (280 sq mi) municipality is the 155th largest by area out of the 357 municipalities in Norway. Overhalla Municipality is the 205th most populous municipality in Norway with a population of 3,924. The municipality's population density is 5.6 inhabitants per square kilometre (15/sq mi) and its population has increased by 5.1% over the previous 10-year period.

The municipality of Overhalla was established on 1 January 1838 (see formannskapsdistrikt law). During the 1960s, there were many municipal mergers across Norway due to the work of the Schei Committee, although Overhalla's borders were only slightly modified. On 1 January 1964, the Galguften and Hauknes area (population: 15) of Høylandet Municipality (on the southern shore of the lake Eidsvatnet) was transferred to Overhalla Municipality.

On 1 January 2018, the municipality switched from the old Nord-Trøndelag county to the new Trøndelag county.

The municipality (originally the parish) is named Overhalla (Old Norse: œfri hálfa), an old name for the area. Historically, the Namdalen district was divided in two parts: "the upper half" and "the lower half". The first element comes from the word efri which means "upper". The last element derives from the word halfr which means "half". Thus, the name means "the upper half (of Namdalen)". The municipality of Overhalla today is, however, just a fraction of the old part of what was historically considered œfri hálfa. Historically, the name of the municipality was spelled Overhallen. On 3 November 1917, a royal resolution changed the spelling of the name of the municipality to Overhalla.

The coat of arms was granted on 2 June 1989. The official blazon is "Or, sevense crosses gules in annulo" (Norwegian: I gull sju røde kors som danner en sirkel). This means the arms have a field (background) has a tincture of Or which means it is commonly colored yellow, but if it is made out of metal, then gold is used. The charge is a circular arrangement of seven greek crosses. The design was inspired by a 1344 seal used by local peasants on a document regarding the coronation of King Håkon Magnusson. The seal depicts a building topped with a cross similar to those on the coat of arms and at the local Ranem Church. The arms were designed by Harald Ekseth. The municipal flag has the same design as the coat of arms.

The municipality includes part of the lake Eidsvatnet, from which the river Bjøra flows into the river Namsen, which runs from the east to the west. By the time it reaches the border with Namsos Municipality, the river Namsen is already brackish and influenced by the tides the ocean. The river Nordelva also empties into the estuary here. On the south side of the Namsen river, there is an area of mountains and mountain lakes. The highest point in the municipality is the 726.51-metre (2,383.6 ft) tall mountain Reinsjøfjellet. The Bangsjøene lakes form the border with Snåsa Municipality. The western approaches to Geitfjell lies in Overhalla Municipality, while the summit lies in Grong Municipality. The southern tip of the lake Storgrønningen lies in Overhalla Municipality, while the vast majority of the lake lies in Høylandet Municipality.