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, Skage, 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 located in the municipality.
The municipality is the 155th largest by area out of the 356 municipalities in Norway. Overhalla is the 207th most populous municipality in Norway with a population of 3,817. The municipality's population density is and its population has increased by 3.8% 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 (on the southern shore of the lake Eidsvatnet) was transferred to Overhalla.
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 (œfri hálfa) which means "the upper half (of Namdalen)". Historically, the Namdalen district was divided in two parts: "the upper half" and "the lower half". The municipality of Overhalla today is, however, just a fraction of the old part of what was historically considered œfri hálfa. Historically, the name was spelled Overhallen.
The coat of arms was granted on 2 June 1989. The official blazon is "Or, sevense crosses gules in annulo" (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.