Grong is a municipality in Nord-Trøndelag county, Norway. It is part of the Namdalen region. The administrative centre of the municipality is the village of Medjå. Other villages in the municipality include Bergsmoen, Formofoss, Gartland, and Harran.
Grong was established as a municipality on 1 January 1838 (see formannskapsdistrikt). On 1 January 1901, the northwestern district of Høylandet (population: 1,046) was separated from Grong to form its own municipality. On 1 January 1923, the northeastern district of Røyrvik (population: 392), the northwestern district of Namsskogan (population: 469), and the central district of Harran (population: 630) were all split from Grong to form separate municipalities. This left a vastly smaller municipality of Grong with only 1,272 residents. On 1 January 1964, the municipality of Harran (population: 1,085) was merged back into Grong.