is a municipality in Innlandet county, Norway. It is located in the traditional district of Hedemarken. The administrative centre of the municipality is the town of Brumunddal. Other settlements in Ringsaker include the town of Moelv and the villages of Furnes, Kvål, Kylstad, Mesnali, Nydal, Rudshøgda, Stavsjø, Tingnes, and Byflaten.
The municipality is the 77th largest by area out of the 356 municipalities in Norway. Ringsaker is the 30th most populous municipality in Norway with a population of 35,073. The municipality's population density is and its population has increased by 5.7% over the previous 10-year period.
The municipality of Ringsaker 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. On 1 January 1964, the municipality of Ringsaker (population: 16,490) was merged with the neighboring municipalities of Furnes (population: 7,288) and Nes (population: 4,184) plus the Hamarsberget and Vikersødegården exclave areas of the municipality of Vang (population: 34) to create the new, larger municipality of Ringsaker. On 1 January 1965, a part of Ringsaker (population: 100) was transferred to the neighboring Hamar Municipality. On 1 January 1967 there was a municipal land swap between Vang and Ringsaker municipalities. The Stav, Valsigsvea, and Arnkvern Nedre areas of Vang (population: 50) was transferred to Ringsaker Municipality and the Stensby and Holmlund areas of Ringsaker (population: 114) was transferred to Vang.
On 1 January 1992, the parts of the Stensby, Hanstad, Viker, and Stammerud areas of Ringsaker (population: 224) were transferred to the neighboring Hamar Municipality.
The municipality (originally the parish) is named after the old Ringsaker farm (Ringisakr or Hringisakr) since the first Ringsaker Church was built there. The first element is the genitive case of ringir or ringi which has an unknown meaning.